I. Introduction

For much of American history, criminal defendants could not testify.1 In fact, it was only a quarter century ago that the Supreme Court swept away the last vestiges of the testimonial prohibition, belatedly recognizing a criminal defendant’s constitutional “right to take the witness stand.”2 To justify its atextual ruling, the Court channeled “the considered consensus of the English-speaking world” that there could be “no rational justification for prohibiting the sworn testimony of the accused.”3 Legal commentators applauded. Despite regular appeals to historical intent and textual fidelity in other contexts, judges and academics across the ideological spectrum embrace the upstart constitutional right as an enlightened evolution, akin to the elimination of trial by ordeal.4

It was not always so. As reformers first ushered in an age of defendant testimony through statutes over a century ago, critics predicted dire consequences for the purported beneficiaries of the new right. Commenting on his state’s newly enacted statute in 1867, Massachusetts’ Supreme Court Justice Seth Ames argued that allowing defendant testimony would “destroy[] the presumption of innocence.”5 In light of jurors’ inevitably negative reaction to defendants who chose silence, Ames predicted defendants would have “practically no option at all”; the new right will “compel the defendant to testify” and “all will use it.”6

Judge Ames was prescient in some respects and spectacularly wrong in others. In particular, his prediction that “all” defendants would testify did not come to pass. In modern times, only about half of criminal defendants take the witness stand.7 Notably, refusing to testify is not limited to guilty defendants. Around 40% of defendants later exonerated by DNA evidence declined to testify at their initial trials.8 As this figure indicates, defendants with important stories to tell frequently sit silently while their attorneys plead their case.9

The remarkable prevalence of defendant trial silence can only be understood by reference to the consequences for those who do take the witness stand. While each case presents a variety of tactical considerations, the most concrete deterrent to testifying is a product of the evidence rules concerning prior crimes.10 In the modern era, most defendants who stand trial have a criminal record that predates the charged crime.11 This nation’s ongoing struggle with mass-incarceration suggests that the striking prevalence of trial defendants with prior convictions will only increase in the coming years.12

American evidence rules generally exclude evidence of prior crimes.13 But when defendants testify, their criminal record becomes eligible for admission as “impeachment.”14 Once a jury learns of a defendant’s record, it is more likely to convict—a phenomenon labeled here the “prior offender penalty.”15 For example, famed DNA exoneree Ronald Cotton testified at trial to his innocence of a violent break-in and rape.16 He was then impeached with his past crimes, including “a prior conviction of assault on a female with intent to commit rape and a prior conviction of breaking and entering.”17 After hearing of Cotton’s earlier convictions, the jury disbelieved his (truthful) claim of innocence and convicted.18

Since the choice to testify belongs to the defendant alone, a common reaction to the looming admissibility of prior crimes is to decline to take the witness stand. The customary defense tactic of remaining silent to avoid impeachment (or other harms) creates a new risk, however.19 When defendants do not testify, they suffer a different penalty—labeled here the “silence penalty.” It is the interplay between the “silence penalty” and the “prior offender penalty” that typically determines whether defendants testify, and how jurors react to that choice.20

The shaky historical pedigree and critical tactical importance of defendant testimony should make the topic a subject of spirited academic inquiry. Yet the literature is surprisingly thin. The legal and academic understanding of defendant testimony and trial silence has remained unchanged for decades. To the extent it is addressed at all, the modern discourse centers on a nebula of poorly-understood evidence doctrines and vacuous tactical folklore. As another commentator aptly summarized: “What has been largely missing from the debate are facts.”21

This Article seeks to reanimate the academic discourse on defendant testimony and highlight its importance to current criminal justice debates. The analysis focuses on empirical evidence, a key element of any serious discussion in the increasingly polarized criminal justice space. The data come from three sources. First, the Article (Part II) synthesizes the pertinent social science literature which contains a wealth of informative, experimental mock juror studies often overlooked by legal commentators. Next, the Article (Part III) presents the results of a new, 400-person mock juror simulation designed to fill a significant gap in the existing body of experimental data. Third, the Article (Part IV) explores observational data from real trials, drawing primarily from the well-known, but perplexing22 multi-jurisdictional study of felony trials conducted by the National Center for State Courts (NCSC). By tying together findings from the social science literature, the new mock jury simulation, and data from real trials, the Article is able to present (and support) a new, data-driven account of how jurors react to defendant testimony and its absence.

Analysis of the data summarized above unlocks a variety of insights. Perhaps the most intriguing of these is the underappreciated power of trial silence. As explained below, the evidence suggests that, broadly speaking, the “silence penalty” harms defendants nearly as much as the more universally-dreaded “prior offender penalty.” That is, a defendant who remains silent at trial suffers about the same damage to his acquittal prospects as a defendant who testifies and is “impeached” with a prior conviction.

The implications of this “parallel penalty” thesis (explored in Part V) are powerful for defendants, their attorneys and anyone concerned with the fairness and accuracy of our criminal justice system.23 For defendants and their attorneys, the tactical implications are clear. The lesson of the data reported in this Article is that defense attorneys should not counsel trial silence lightly. Instead, they should seek to have their clients testify absent a strong case- or defendant-specific factor that dictates silence.24 A criminal record may present such a factor, but in many circumstances, even the disclosure of a criminal record will be less damaging than the underappreciated silence penalty.

In a world where guilty pleas make up over 90% of convictions, trial tactics are only a part of the story.25 The real action in the criminal justice system happens pretrial and the parallel penalty dynamic operates there as well.26 The parallel penalties awaiting defendants with a criminal record at trial increase the pressure to forego trial and plead guilty. Defendants have only two trial options: testify or remain silent. If both options generate powerful penalties, guilty and innocent defendants will rationally bargain away an (illusory) presumption of innocence for a modicum of mercy.

Finally, the empirical evidence presented in this Article vindicates the handful of 19th century critics who objected to allowing defendant testimony in the first place. The critics’ reasoning does not map perfectly onto modern times, but the spirit of their critique rings true. For most defendants, including those with prior convictions and those who decline to testify, the right to testify probably does more harm than good.27 Distressingly, the data further suggest that this harm stems from juror assumptions about both defendant silence and prior convictions that, as far as the law is concerned, have no place in a criminal trial.28

II. Deciding Whether to Testify or Remain Silent

Judge Ames’ forecast that “all” criminal defendants would testify falls flat in the modern era. But Ames was right that for many defendants the privilege to testify is more curse than blessing. As we will see, for most defendants the choice between testifying or remaining silent is an exercise in damage control.29 This Part isolates and analyzes the two options, with a particular focus on experimental evidence from the social science literature.

A. The Prior Offender Penalty

Justice Benjamin Cardozo famously stated that “character is never an issue in a criminal prosecution unless the defendant chooses to make it one”; as far as the law is concerned, “a defendant starts his life afresh when he stands before a jury, a prisoner at the bar.”30 Unfortunately, Cardozo’s flowery sentiment only applies to silent defendants. When a defendant testifies, he becomes subject to cross-examination just like any other witness. The defendant-witness is “duty-bound to speak truthfully, entitled to the same privileges, and exposed to the same perils of impeachment, stress, embarrassment, and so on.”31

One longstanding method of impugning a witness’s sincerity is cross-examination regarding past crimes.32 Oliver Wendell Holmes explained the operative logic in 1884: A prior violation of the law indicates a “general readiness to do evil” and “from that general disposition” the jury may “infer a readiness to lie in the particular case.”33 As the evidence is admissible only with respect to the “witness’s character for truthfulness,”34 judges must instruct juries that the testifying defendant’s “prior convictions should only be used to judge [the defendant’s] credibility rather than his propensity to commit crimes.”35 When combined with the defendant’s right to testify, this evidentiary framework generates a peculiarity of the American trial system: The admissibility of a defendant’s criminal record typically depends on the defendant’s decision whether or not to take the witness stand. If the defendant testifies, his record will generally be admitted.36 If the defendant does not testify, it generally will be excluded.37

Social scientists have produced a valuable body of experimental research regarding the impact of prior convictions. This research reveals that “[j]urors are more likely to convict an accused if they receive information about previous convictions than if they do not.”38 That is no surprise. Admissible evidence generally damages one side or the other. Credibility impeachment with prior convictions should be no exception. Yet the research suggests that prior conviction impeachment does not operate as the law intends. Rather than relying on prior convictions as evidence of the defendant-as-witness’s character for truthfulness, jurors appear to rely on convictions as forbidden criminal propensity evidence—“generalizing a defendant’s earlier bad act into bad character and taking that as raising the odds that he did the later bad act now charged.”39

If jurors used prior convictions as the law intends, past crimes that undermined the defendant’s truthful character, such as perjury, would be the most damaging to defendants’ chances of acquittal. Yet empirical research has shown that even when properly instructed, mock jurors convict most readily when presented with prior crimes that are similar to the charged crime, not, as the operating legal theory would predict, when presented with crimes related to dishonesty.40 The stronger salience of similar crimes as opposed to dishonesty crimes in generating guilty verdicts suggests that jurors use prior convictions to engage in legally forbidden criminal propensity reasoning.

A widely-cited study by Roselle Wissler and Michael Saks presented mock jurors with scenarios that included prior convictions for the same crime and prior convictions for perjury.41 The mock jurors were instructed on the proper use of the prior convictions through a variant of the standard instruction used in Massachusetts trials.42 Jurors in a mock murder case convicted 70% of the time when the defendant had a prior murder conviction, but only 50% of the time when the defendant had a prior perjury conviction.43 Other jurors given a mock auto theft case convicted 80% of the time when the defendant had a prior auto theft conviction, but only 70% of the time when the defendant had a perjury conviction.44 These results suggest that the mock jurors relied on the prior convictions as evidence of the defendant’s criminal propensities, not solely as impeachment.

The Wissler and Saks study, while extensively cited, suffers from some weaknesses. It relies on a relatively small sample size and its most powerful finding arises from an unusual scenario of a defendant with a prior murder conviction.45 Nevertheless, other researchers have reported the same result in similarly constructed mock juror studies.46 One portion of the new mock jury simulation presented in Part III tested for the same phenomenon, using a larger sample size and more typical crimes. Shoring up the findings referenced above, the mock juror simulation obtains similar results. The jurors in the simulation convicted more often when the defendant was impeached with a prior similar crime (82%) than when he was impeached with a dissimilar dishonesty crime (73%).47

Another social science study reviewed comments made by mock jurors during deliberations. It found that juror statements about prior convictions “tended not to center around the credibility issue” but instead “juries were more likely to discuss a prior conviction (particularly one for a similar crime) as a basis for inferring that the defendant is the type of person who is capable of committing the current offense.”48 Data from real trials points to the same conclusion. Analyzing data gathered from post-trial surveys with actual jurors, Valerie Hans and Theodore Eisenberg found that jurors’ self-reported assessments of the defendant’s credibility did not correlate with the admission of prior convictions.49 This suggests that real jurors are unimpressed with the legally sanctioned purpose for the admission of prior convictions.

Courts themselves acknowledge the danger that jurors will be unable to separate the proper from improper use of prior crimes evidence. The standard framework for assessing the admissibility of prior convictions as impeachment requires judges to consider, inter alia, “[t]he similarity between the past crime and the charged crime.”50 The introduction of similar crimes, the courts recognize, generates “inevitable pressure on lay jurors to believe that ‘if he did it before he probably did so this time.’”51 Although judges routinely admit prior convictions offered as impeachment, even for similar crimes,52 their recognition of this consideration stands as official acknowledgement of the difficulty jurors face in resisting the prohibited “criminal character” inference.

The academic literature includes one contrary claim that must be addressed. Two of the most prominent scholars to address prior convictions in recent years, Larry Laudan and Ronald Allen, argue that the empirical evidence regarding “how mock jurors handle prior crimes information” is “all over the map” and “contradictory.”53 They assert that a judge who believed that “prior crimes evidence has only a very limited effect on jury decisions” would find “plenty of studies to back up that prior disposition.”54 Laudan and Allen recognize that their claim runs counter to the (“clumsily cobbled together”) “conventional wisdom,” the views of academics, judges and “American evidence law.”55 Nevertheless, the prominence of these authors and the forcefulness of their assertion makes it necessary to examine their contention in some detail.

Laudan and Allen identify five studies that support the consensus described above—that when jurors learn of the defendant’s prior convictions, acquittal prospects drop.56 To make out the claim that the empirical evidence is nonetheless “all over the map,” Laudan and Allen cite four other studies that they believe point in the other direction.57 The four studies do not support Laudan and Allen’s contention. Three of the studies are easily dispensed with on the ground that they do not consider prior conviction evidence at all. Instead, in all three studies mock jurors learned that the defendant had made incriminating (or exculpatory) statements.58 The jurors were then instructed to disregard the statements because they were obtained through an illegal wiretap.59 These studies may be pertinent to the broader issue of jury instructions, but they concern a different species of evidence and altogether different considerations (e.g., police misconduct).60

Only one of the four studies Laudan and Allen cite for the proposition that the evidence on “how mock jurors handle prior crimes information” is “all over the map” concerns prior crimes. But the portion of that 40-year-old London61 study that supports Lauden and Allen’s contention is easily distinguished. The study presented a simulated rape trial of two co-defendants, and noted that mock jurors convicted at similar rates whether or not they heard about one of the co-defendant’s prior rape conviction. Importantly, the study’s authors introduced the prior conviction in an unusual manner. In real trials and in most simulations, prior crimes are introduced through unassailable sources such as an official record or the defendant’s own admission. Judges then instruct jurors to use the conviction only as impeachment, validating its accuracy. In the London study, however, the conviction was “let slip” in the other co-defendant’s testimony—and then the judge instructed the jurors to disregard it completely.62 This confounds the analysis. Jurors in the London study might have resisted the normal impact of prior convictions because they disbelieved the co-defendant’s offhand assertion that his accomplice had previously committed a rape—particularly as each defendant stood to benefit by casting blame on each other.63

In sum, the prior conviction finding cited by Laudan and Allen that counters the broad consensus on prior crimes evidence can be explained as stemming from an atypical study design. The empirical evidence from mock juror experiments is one-sided and clear. The studies suggest that the introduction of prior conviction evidence substantially damages defendants’ chances for acquittal, primarily through a legally prohibited “criminal propensity” inference.64

B. The Silence Penalty

The preceding section analyzed experimental evidence that illustrates the harm done to a defendant’s acquittal prospects when the jury learns of a prior conviction. To avoid this “prior offender penalty,” defendants can, and often do, choose to remain silent at trial.65 As one defense attorney manual explains, when it comes to defendant testimony, “[o]ftentimes . . . silence is golden. The client may be better off saying nothing and merely giving the appearance of a choir boy.”66 Yet, as this section reveals, the empirical evidence also demonstrates that remaining silent comes at a price.

There is little doubt that jurors view defendants’ silence with a cynical eye. A juror interview for the “Serial” podcast, a popular investigative series about a controversial murder conviction, illustrates the problem defendants face:

Reporter: “Did it bother you guys as a jury that [the defendant] Adnan [Syed] himself didn’t testify, didn’t take the stand?” Juror: “[Y]eah, that was huge. We all kinda like gasped . . . we were all just blown away by that. You know, why not, if you’re a defendant, why would you not get up there and defend yourself, and try to prove that the State is wrong, that you weren’t there, that you’re not guilty? We were trying to be so open minded, it was just like, get up there and say something, try to persuade, even though it’s not your job to persuade us . . . .”67

The sentiment is not unusual. In public opinion surveys, about half of respondents say that a defendant who does not testify “is probably guilty” or “has something to hide.”68

Table 1: 2002 Public Opinion Poll69

The apparently widespread belief that an innocent defendant would testify looms ominously over jury deliberations involving silent defendants.

The social science literature, and particularly research by psychology professor David R. Shaffer, supports the conclusion that jurors punish defendants for refusing to testify. Consistent with that of other researchers, Shaffer’s research reveals that mock jurors convict more readily when defendants appear to be withholding information.70 In one study, a group of mock jurors were told that a defendant, after testifying on direct, invoked his Fifth Amendment privilege not to incriminate himself in response to a question on cross-examination.71 These jurors convicted significantly more frequently.72 The study concludes that, “the defendant who gives the appearance of withholding crime-relevant information is likely to be viewed guilty and deserving of conviction.”73

Shaffer suspected that jurors would be less punitive when the defendant’s refusal to answer questions took the form of the invocation of the venerated Fifth Amendment right not to take the witness stand.74 With a co-author, he staged a sophisticated trial simulation where jurors were presented with either: (1) a defendant who did not testify; (2) a defendant who testified, but refused to answer a potentially incriminating question during cross-examination; or (3) a defendant who testified normally without refusing to answer any questions.75 The jurors were instructed, as applicable, that they could not hold the defendant’s invocation of the Fifth Amendment privilege against him.76 This time, Shaffer uncovered even more compelling evidence of a silence penalty. Two thirds of the juries that rendered verdicts in the scenarios where the defendant withheld information (either by declining to testify or refusing to answer a specific question) rendered a guilty verdict.77 By contrast, there were no guilty verdicts in the scenarios where the defendant did not invoke his Fifth Amendment privilege.78 Individual juror votes among the juries that could not reach a verdict followed the same pattern.79 Importantly, Shaffer found his surmise that jurors might respect the defendant’s choice not to testify at all (as opposed to testifying selectively) disproven. “[A]nalyses of the group verdicts, guilt ratings, and the verdicts of individual jurors revealed that defendants who declined to take the stand were judged just as harshly as their counterparts who refused to answer specific interrogation.”80

Another window into the impact of defendant silence comes from post-conviction case law. The law is stacked against challenges to juror verdicts as evidenced by legal doctrine that verdicts cannot be impeached by juror testimony regarding the content of their deliberations.81 This bar generally extends to “proof that one or more jurors held it against the accused that he failed to take the stand.”82 Still, challenges abound.83 A recent California case illustrates the genre. In Strand v. McDonald, a juror testified that the “defendant’s failure to testify was mentioned between six and twelve times during jury deliberations, by as many as half of the jurors. About one-quarter to one-third of the remarks included the view that ‘if [defendant] was innocent he would have testified.’”84 (Both the federal and state courts upheld the verdict.)85 Given the futility of these claims and the likely reluctance of jurors to broadcast their own malfeasance, the number of cases that raise the issue86 hints at an underlying reservoir of cases where jurors considered the defendant’s failure to testify as evidence of guilt.

The anecdotal and empirical evidence summarized above suggests that just as there is a significant “prior offender penalty,” there is also a powerful “silence penalty.” Although, as Shaffer notes, “how heavily” the silence penalty “weighs” remains an open question.87 The next Parts attempt to answer that question by analyzing the results of a new mock juror simulation and data from real trials.

III. Comparing the Parallel Penalties: A Mock Juror Experiment

The mock juror studies summarized in Part II suggest that (1) jurors will convict more readily when they learn that a defendant has a prior criminal record; and (2) jurors will penalize defendants who do not testify. Yet the literature has a blind spot. Despite a bounty of mock juror studies, no previous study compares the effect of the introduction of a prior conviction against the effect of a failure to testify—the dilemma typically faced by criminal defendants. This Part presents the results of a trial simulation involving 400 mock jurors designed to do just that. As explained below, the simulation detected both a “silence penalty” and a “prior offender penalty.” Most interestingly, the simulation found the penalties to be roughly equal.

A. Experimental Design

The mock juror experiment consisted of a simulated trial of a single defendant for breaking into a store and stealing jewelry. The simulation was designed—and pilot tested—to suggest guilt, but not conclusively. The goal was to construct a straightforward, realistic case that was close enough to engender disagreement, but still representative of a typical American criminal trial.88 (For example, in California the rate of conviction at trial in felony cases is reportedly higher than 80%; in Florida it is around 73%.)89

I recruited mock jurors using the Mechanical Turk employment marketplace. Researchers increasingly rely on Mechanical Turk for academic studies since it facilitates access to a broad range of willing research participants in a cost-and-time effective manner.90 As with jury service, Mechanical Turk users must be at least 18 years of age;91 eligibility was further limited to people located in the United States. A number of studies indicate that Mechanical Turk respondents are preferable in terms of representativeness and diligence to typical academic survey subjects.92 Mechanical Turk respondents, however, can skew younger, more female and more educated than the population at large. This would be problematic in a public opinion survey, but here we are looking at reactions to subtly-altered fact patterns distributed randomly to subsets of the survey group. It seems unlikely in this context that any potential differences between a Mechanical Turk sample and a typical jury pool would warp the results. In short, Mechanical Turk, like other survey tools, is not perfect, but in experiments such as this, can be “a reliable source of experimental data in judgment and decision-making.”93

Four hundred participants agreed to take the survey in exchange for a nominal fee approximating the (pro-rated) federal minimum wage.94 Respondents were routed to an automated, online survey interface that randomly presented one of four case scenarios.95 The scenarios were identical except with respect to whether the defendant testified and, if so, the type of impeachment presented. Respondents who encountered impeachment also received a jury instruction that the prior crime could be considered “only with respect to [the defendant’s] credibility.”96 In the scenarios where the defendant testified, his testimony added no new information. The defendant’s testimony was summarily described as being “consistent with that of” a defense alibi witness whose testimony (that he and the defendant were watching a baseball game at the time of the crime) appeared in all four scenarios.

The four scenarios presented to respondents were as follows:

Table 2

Respondents answered a series of “reading check” questions to ensure that they were, in fact, reading and understanding their respective scenarios.97 At the conclusion of the presentation, the survey instructed respondents that “you should only find the defendant guilty if you believe the evidence establishes his guilt beyond a reasonable doubt.” Participants were then asked how they would vote “as a juror in a criminal case: not guilty or guilty.”

B. Results

Jurors voted to convict in 73% of the cases. The following table reveals the breakdown of guilty votes by scenario, ordered by descending conviction percentage.

Table 3

Approximately 100 distinct mock jurors voted in each scenario. As the above table shows, the conviction rate was highest for Scenario 4 where the defendant testified and was impeached with a prior robbery. The lowest conviction rate occurred in Scenario 2 where the defendant testified and was not impeached with any prior crimes. The other two scenarios—where the defendant did not testify, or testified and was impeached with a criminal fraud conviction—returned similar conviction rates.

The results are consistent with the social science literature presented in Part II. The jury’s learning of prior convictions negatively impacted the defendant’s chances for acquittal. The jurors convicted most often (82%) when they learned that the defendant had a prior robbery conviction. The conviction rate was also elevated (73%) over the no record condition (62%) when the defendant was impeached with a “criminal fraud” conviction. Overall, jurors voted to convict 78% of the time in the two prior conviction conditions, but only 62% of the time when the same testifying defendant was not impeached with any prior crimes. This variance achieves statistical significance.98

These findings also support the critique developed in Part II that prior conviction impeachment does not operate in the manner that the law contemplates. If prior conviction impeachment speaks only to the defendant’s character for truthfulness, crimes of dishonesty would be most damaging. Here, the fraud conviction should have been most damaging since it is a crime that, unlike robbery, speaks directly to truthful character. “Criminal fraud” is one of a handful of offenses specifically referenced in the legislative history to Federal Rule of Evidence 609 and its advisory committee notes as directly “bearing on the accused’s propensity to testify truthfully.”99 Instead, in this experiment, the robbery conviction—an offense that was likely seen by lay participants as similar to the charged jewelry store burglary—had a larger negative impact. This suggests (consistent with the prior research discussed in Part II.A) that jurors indulged a forbidden, criminal propensity inference.

Finally, and most interestingly, the results support the “parallel penalty” hypothesis developed in the preceding sections. Consistent with Shaffer’s research described in Part II.B, the results reveal a clear “silence penalty.” Respondents convicted 76% of the defendants who remained silent, but only 62% of equally situated defendants who testified (but added no facts).100 Again the difference is statistically significant.101 Further, the weight of the silence penalty appears to be roughly equivalent to the “prior offender” penalty. Combining the two prior conviction conditions (Scenarios 3 and 4) results in a 78% conviction percentage. This is almost identical to the conviction percentage for Scenario 2 where the defendant did not testify and was not impeached with any past crime—76%. These findings support a hypothesis that both remaining silent at trial and the admission of a defendant’s prior convictions substantially decrease the prospects for acquittal. And the operative “silence” and “prior offender” penalties appear to harm defendants to a similar degree.

IV. Data from Real Trials

Mock juror studies only tell us so much. No matter how clear the patterns that emerge in juror simulations, doubts will persist as to whether these simulations accurately reflect juror decision making in actual trials. A clear picture of how real jurors react to defendant testimony requires data from real trials.

The dataset with the highest potential to unlock the mysteries of defendant testimony comes from the National Center for State Courts (“NCSC”).102 In 2000 and 2001, the NCSC surveyed attorneys, judges and jurors participating in felony cases at four sites: Los Angeles, Phoenix, the District of Columbia, and the Bronx.103 The surveys solicited a broad range of case-specific information as part of an inquiry into the frequency and causes of hung juries. The information included whether the defendant testified, admission of prior convictions, and case outcomes.104 The surveys also asked jurors and judges to assess the strength of the prosecution’s evidence.105

Analyzing data from real cases raises a number of challenges. The challenges range from specific quibbles with the NCSC data set to big picture questions about the daunting variability of criminal trials. With respect to specific quibbles, the NCSC data on “criminal record” is not ideal. It captures “criminal record” broadly but imprecisely, lumping together all convictions and arrests. The survey asked: “During the trial, did the jury become aware of the defendant’s criminal history (if any)?”106 Respondents answered: “Yes,” “No” and “Not applicable (no known arrests/convictions).”107 Important information that is not captured by this question is whether an arrest led to conviction and whether the conviction was for a petty offense (e.g., misdemeanor) that typically cannot be used as impeachment.108 More subtle ambiguity comes from data coding choices. If a jury acquitted a defendant of murder, but convicted of the lesser (but perhaps uncontested) offense of unlicensed gun possession, is that a conviction or an acquittal?109 What about hung juries? To minimize empirical objections and unintended variation, and facilitate comparison to other articles that analyze the NCSC data, this Article draws primarily on the published analysis of the NCSC data by Eisenberg and Hans. These prominent legal empiricists have already extracted the most pertinent data regarding defendant testimony from the NCSC data set for their article on the impact of prior convictions.110

Finally, no study of real cases can capture all the variables that influenced a jury verdict. Instead, the hope is that randomly pooled variation in a sufficient number of cases will permit the detection of broad patterns that reflect underlying realities. Definitive conclusions from the NCSC data alone will be impossible. Like the perceptions of judges and attorneys who work in the criminal justice system, and the mock juror simulations discussed above, the NCSC data simply offer another place to look in an effort to understand how jurors react to defendant testimony.

With the above caveats, the NCSC data support many of the propositions already discussed. Only about half of defendants testified.111 Defendants with prior records were less likely to testify.112 And those who did testify were more likely to have their criminal records presented to the jury.113 Defendants who were members of racial minority groups testified less frequently, but this finding was only “marginally statistically significant” and can be attributed to “different rates of prior criminal records”; the few female defendants testified more frequently than male defendants.114 Interestingly, the reported evidentiary strength of the cases did not differ significantly between those cases where the defendants did and did not testify.115

A. The NCSC “Paradox”

The NCSC data present what other commentators have described as a “seeming paradox” and “puzzling” result.116 The paradox begins with the not-so-surprising finding that juries convicted at a much higher rate if the defendant had a criminal record (76%) than if the defendant had no record (56%).117 The perplexing aspect of the data is that juries convicted defendants with prior crimes at approximately the same rate whether their convictions were revealed to the jury or not.118 Thus, the NCSC data’s surprise for researchers was: “It is whether or not the defendant has a criminal record—not whether the jury learns about it—that has the greatest influence on the acquittal/conviction decision.”119

While others have flagged this curious finding,120 no one has produced a compelling explanation for it. Larry Laudan and Ronald Allen, who make this finding the centerpiece of a provocative article, grapple with the question most directly.121 They conclude that the NCSC data show that the purportedly devastating impact of the admission of prior crimes evidence is a myth that has bedazzled attorneys, policymakers, and scholars for decades.122 “Admitting evidence of prior crimes,” they argue, “apparently leads to few additional convictions.”123 They surmise that jurors “are generally able to infer who has priors” regardless of whether the prior crimes are made known to them in the evidence.124

For ease of reference, I will call Laudan and Allen’s hypothesis the “jury sophistication” hypothesis. In light of their hypothesis, Laudan and Allen disparage efforts through evidence rules and litigation strategy to keep prior convictions out of evidence as “self-defeating,” and label academic criticism of the admission of prior crimes “unnecessary hyperbole.”125 If Laudan and Allen’s interpretation is correct, volumes of scholarly articles and judicial opinions, along with a number of evidence rules—what Laudan and Allen label “the criminal justice system’s fetish about excluding prior crimes”126—must be rewritten; and attorneys have for decades been pointlessly fighting over, and tailoring trial strategies to, the admission of prior convictions.127

As explained below, Laudan and Allen’s ground shaking juror-sophistication hypothesis is not the best explanation for the NCSC data. Their theory is initially undermined by the experimental data analyzed in Part II.128 This experimental evidence reveals that when mock jurors are told that the defendant has a prior record, they convict more readily. This finding is difficult to reconcile with Laudan and Allen’s claim that real jurors are indifferent to being told about prior crimes evidence. As discussed earlier, Laudan and Allen’s response to this challenge—that the mock juror evidence is “all over the map”—is incorrect.129 Further, Laudan and Allen’s hypothesis contradicts the near-universal views of practitioners, judges, academics and policymakers that informing jurors of prior convictions powerfully impacts defendants’ prospects.130 Everyone else may be wrong, of course, but the existence of such a robust countervailing consensus raises a red flag.

There are a number of other possible explanations for why defendants with a criminal record fare worse at trial regardless of juror awareness of the prior record. This Article posits the “parallel penalty” hypothesis as the best explanation,131 but others come to mind as well. For example, a criminal record correlates with lower income.132 Lower income means defendants will be unlikely to afford a (perhaps superior) private attorney. But as paid attorneys appear in less than 18% of criminal cases,133 this “free-attorney hypothesis” can only be a partial explanation. Further, elite public defender offices in large cities like those studied in the NCSC survey (e.g., the District of Columbia’s Public Defender Service or the Bronx Defenders) may actually outperform retained counsel.134

Another explanation could be the relationship between criminal history and an increased likelihood of pretrial detention.135 Defendants held pending trial generally fare worse than those released.136 But again, this “pretrial detention hypothesis” seems at best a partial explanation. As explained below, neither these explanations nor the one posited by Lauden and Allen convincingly account for the NCSC data.

The “parallel penalty” hypothesis presented in this Article represents the best explanation for the “puzzling” NCSC data. Under this hypothesis, the equivalent conviction rates for defendants with criminal records do not result from jurors detecting hidden convictions, or variations in lawyer quality or pretrial release. Rather, unrevealed convictions inflict harm indirectly by causing defendants to remain silent at trial, leading to a “silence penalty.” If this alternative manifestation of a criminal record harms defendants roughly as much as the introduction of prior convictions, the NCSC data fall neatly into place.

The “parallel penalty” hypothesis is not as jarring to the conventional wisdom as Laudan and Allen’s juror sophistication hypothesis, but it nonetheless demands a deeper appreciation of the importance of trial silence to American jurors. The balance of this Part analyzes specific slices of the NCSC data to determine whether the “parallel penalty” hypothesis or the alternatives better explain the data. (Each subsection below includes an introductory table to highlight the NCSC data slice to be discussed.)

B. Defendants Without Priors: Testifying v. Non-Testifying

Table 4

137

We begin with the data for defendants without prior convictions. This comparison provides the most straightforward evidence that a silence penalty and not jury sophistication about hidden criminal records, or other factors that correlate with criminal records, explains the “seeming paradox.” Table 4 shows that when defendants without prior convictions testified, they were convicted 41% of the time—a startlingly low percentage considering the high overall conviction rates.138 When defendants without prior convictions did not testify, their conviction percentage skyrocketed to 70%.139

Thus, for defendants without prior convictions, testifying coincided with an almost doubling of the chances of acquittal. As this variation emerges among defendants without a criminal record, the “pretrial detention” and “free-attorney” hypotheses cannot explain it. Of course, case-specific facts undoubtedly play a key role and many variables are not captured in the NCSC study. Still, the data presented in Table 4 constitute circumstantial evidence that a “silence penalty” exists in the American trial system. Like the mock jurors discussed in Part III, jurors in real cases appear to be more willing to convict defendants who remain silent at trial.

C. Defendants with Priors: Testifying v. Non-Testifying

Table 5

140

The analysis for defendants with prior convictions is more complex but again supports the parallel penalty hypothesis. Just as the silence penalty hurts defendants without prior records who remain silent, it should harm defendants with prior convictions who decline to testify. But the silence penalty will not be as readily identified for these defendants. Testifying strongly correlates with the introduction of prior convictions.141 This means defendants with prior convictions can typically only avoid the silence penalty by (testifying and) suffering a prior offender penalty instead. Thus, the powerful benefit from testifying that appears in Table 4 should not reappear in Table 5. Any benefit prior offender defendants gain by avoiding the “silence penalty” will be offset by a “prior offender penalty.”

Rather than reflecting the benefits of testifying, data broadly comparing prior offenders who testify to those who do not should reflect the relative powers of the silence and prior offender penalties. (Recall that evidentiary strength did not differ significantly between cases with testifying and non-testifying defendants.)142 A possibility suggested by the juror simulation discussed in Part III is that the two penalties are roughly equivalent.143 If so, we would expect that the conviction percentages for defendants with priors will remain about the same whether they testify or remain silent. This fits the NCSC data. Table 4 reflects that defendants with priors who testified were convicted about 77% of the time.144 Defendants with priors who declined to testify were convicted about 72% of the time.145

Concededly, the rough equivalence of the conviction rates between prior offenders who testify and those who remain silent also supports Laudan and Allen’s juror sophistication hypotheses. It could be, as they argue, that jurors are somehow correctly divining that these silent defendants have prior convictions and penalizing accordingly. Similarly, the results could also support the free-attorney and pretrial detention hypotheses. Under these hypotheses, no matter what tactic this subset of defendants choose, their disproportionate inability to hire private counsel and secure pretrial release dominates acquittal prospects. Note, however, that contrary to the empirical evidence presented so far, all of these competing hypothesis only fit the NCSC data if there is no silence penalty. Under these alternative theories, silence has no negative effect. Table 5 reflects that defendants with prior crimes who testified were convicted at least as often as those who remained silent. Thus, while each of the posited theories can claim some support from this slice of the NCSC data (Table 5), the parallel penalty hypothesis (i.e., a rough equivalence of the silence and prior offender penalties) provides a stronger explanation for the equivalent conviction rates. Juries are quick to convict defendants with prior records if they do not testify or if they testify and are impeached with their prior crimes, and the respective penalties in either scenario are roughly the same.

The results hold if we look at a purer (if smaller) comparison of the prior offender and silence penalties by comparing defendants with a prior record who do not testify—and whose convictions are not disclosed—with defendants who do testify and whose convictions are disclosed. Juries convicted defendants who successfully hid their prior record by remaining silent in 71.4% of cases.146 Juries convicted defendants who testified and had their record disclosed in 77.8% of cases.147 Interestingly, the NCSC data here closely tracks the trial simulation described in Part III, where mock jurors convicted non-testifying defendants 76% of the time and convicted impeached defendants 78% of the time.148

D. Non-Testifying Defendants: Priors v. No Priors

Table 6

149

A silence penalty should harm defendants equally regardless of whether they have a criminal record. If, however, jurors are adept at detecting undisclosed criminal records, as Laudan and Allen propose, silent defendants with criminal records will fare worse than those without. Similarly, if income effects of a prior record or likelihood of pretrial release drive the data, we should see a broad criminal-record-related variance between silent defendants. Instead, the NCSC data summarized in Table 6 strongly supports the parallel-penalty hypothesis.

Table 6 shows that the conviction rate for defendants with a prior record who declined to testify (72%)150 is almost identical to the conviction rate for defendants without a prior record who declined to testify (70%).151 This is what we would expect if a silence penalty influences the outcome. As the jury generally remains ignorant of any prior convictions when the defendant declines to testify, both sets of non-testifying defendants should suffer the same single penalty (the silence penalty). The jury never hears of the non-testifying prior offenders’ criminal records and so the conviction rates of the two groups of non-testifying defendants should be roughly equal. The NCSC data (Table 6) fits, revealing an almost identical likelihood of conviction. To jurors, these non-testifying defendants are broadly indistinguishable, and they suffer similar outcomes. If jurors were somehow detecting prior convictions, as Laudan and Allen claim, we would expect a different result. Similarly, if defendants with prior records were suffering worse outcomes across the board due to subpar attorneys or pretrial detention, the data should look different.

E. A Touch of Discordant Data

The parallel penalty hypothesis appears to fit the NCSC data better than the alternatives, but it is not a perfect fit. Assuming the silence penalty is held constant, the parallel penalty theory predicts that the “prior offender penalty” would only appear when the jury is aware of the defendant’s prior record. Yet in one slice of NCSC data, jury awareness of a prior record does not have the anticipated effect on trial outcomes. Among testifying defendants with prior convictions, the conviction rate was only slightly lower (76.6% vs. 77.8%) when their convictions remained unknown to the jury.152 All things being equal, the parallel penalty hypothesis predicts that the conviction rate for prior-offender defendants who testify and are not impeached would be relatively lower since those defendants should not suffer the “prior offender penalty.” This is the one cell of the NCSC data that the parallel penalty hypothesis struggles to explain.153 As we are dealing with real cases, the most likely explanation is that case-specific factors in this relatively modest sample of unusual cases (where defendants testify despite a criminal record, but are nevertheless not impeached with that record in cross-examination) skew the expected percentages.

Indeed, this curious finding drew the attention of Eisenberg and Hans, who scoured the NCSC data for evidence of the impact of the disclosure of prior convictions.154 They determined that the relatively similar conviction rates in this data slice obscured important variance in evidence strength. With evidentiary strength factored in, the prior offender penalty resurfaces as predicted: “[J]ury knowledge of prior criminal history is significantly associated with conviction in weak [prosecution] cases and not significantly associated with conviction in strong cases.”155

Eisenberg and Hans’s further exploration of this data helps the case for the parallel penalty theory and also highlights an important point. The silence and prior offender penalties push juries toward convictions, but they are by no means dispositive. Facts matter most.156 The smaller the number of cases, the higher the risk that unmeasured distinctions across case categories will overwhelm any prior offender or silence penalty.

In sum, while one narrow slice of the NCSC data does not support the parallel penalty hypothesis, the variance can be explained. Deeper statistical analysis of this slice by Eisenberg and Hans hints at variation in case characteristics that skew the observed percentages. Consequently, the parallel penalty hypothesis remains an attractive explanation of the NCSC data overall.

The parallel penalty theory fits the NCSC data fairly well—no small feat given the daunting variability of criminal trials. The parallel penalty hypothesis is also consistent with the extant experimental evidence summarized in Parts II and III, and refines (rather than defies) the decades-old collective wisdom of judges, practitioners, academics and American evidence rules.157 Although there is undoubtedly more to this complex story, the parallel penalty hypothesis fits the empirical data better than the alternatives and provides a promising theoretical framework for how American jurors react to defendant testimony and its absence.

V. Implications

The previous Parts set out the theoretical and empirical case for the parallel penalty hypothesis. This Part discusses the implications of these findings. It begins with tactical implications primarily of interest to practitioners and judges, and then moves to broader implications of chief concern to policymakers and legal scholars.

A. Defendants Should Testify More Often

The empirical data presented in Parts II, III, and IV support two aspects of the conventional wisdom regarding trial tactics. The data reinforce the widely-held view that juries rely on impermissible propensity reasoning to convict when informed that the defendant has previously broken the law (the “prior offender penalty”). The data also suggest that juries punish defendants for remaining silent at trial with a “silence penalty.” Finally, and most strikingly, the data suggest something not captured in the conventional wisdom—that the silence penalty is roughly as damaging as the prior offender penalty.

The surprising power of the silence penalty should give pause to the many defendants without a prior record who demand a trial but then decline to take the witness stand (nearly 40% of trial defendants in the NCSC data).158 By testifying, these defendants could avoid both the silence penalty and the prior offender penalty. Declining to testify, by contrast, puts them in the same position as a defendant with prior convictions. This is a major blow to acquittal prospects and one that (tactically speaking) should be avoided if at all possible.

Of course, case and defendant-specific factors can overwhelm general trends. Defense counsel may believe that juries will react so negatively to their client’s appearance on the witness stand that any silence penalty pales in comparison. Noted defense advocate and law professor Barbara Babcock recognizes all the familiar reasons a defendant without prior convictions might not take the stand, including “that he has no defense . . . . or maybe he is unattractive, even scary, or slow and obtuse so that he could hurt, rather than help himself as a witness.”159 But drawing on her experience as a public defender, Babcock emphasizes that “few defendants who fail to testify win their cases” and notes the critical role for defense lawyers in this equation.160 “[Defendants] who are well-defended rehearse their testimony; the better defended they are the more they rehearse.”161 Babcock further urges counsel to place their client’s testimony in context when necessary. For example, counsel can argue to the jury that the defendant never “deviate[d] from her basic testimony in this case: she is not guilty” despite the “unequal contest” between “my client, with her sixth grade education, who has never before spoken to an audience in public” and the “government prosecutor with her decades of learning, and years of experience.”162 “[T]his argument alone, can make it worth the defendant’s taking the stand, even if his testimony is weak in substance and halting in style.”163 The empirical data marshalled above support Babcock’s contention. Absent “strong affirmative” case or defendant-specific reasons to avoid the witness stand, defendants without prior convictions should testify to avoid a powerful silence penalty.164

Defendants with prior convictions should similarly consider the power of the silence penalty before reflexively embracing the widely-accepted tactic of refusing to testify to hide one’s criminal record. Failing to testify may reduce the impact of a prior conviction, but it only does so by exposing the defendant to a damaging silence penalty. In cases where the defendant’s testimony would add salient facts to the jury’s deliberations or where the prior conviction is not likely to generate negative propensity reasoning (e.g., a different type of crime than the charged crime), testifying may well be the best tactic. Even when impeachment results, the data suggest that, at worst, defendants end up in about the same position they would have occupied if they declined to testify.165 Rather than reflexively silencing defendants, counsel should begin with a presumption that their clients will benefit if they take the witness stand.

Ethical constraints also operate. A lawyer cannot sponsor witness testimony that she knows to be untrue.166 That said, “[t]he conventional defense view also holds that a lawyer ‘knows’ only if the client has told him so categorically.”167

Again we must pause to consider a discordant sentiment by an expert commentator. As already noted, experiments by one of the leading researchers on defendant testimony, psychologist David Shaffer, highlight the damage done to defendants when they do not testify. Shaffer is, nevertheless, “hesitant to advise against” remaining silent at trial because of the results of a study by sociologist Martha Myers.168 Shaffer’s reluctance is worth exploring because, as discussed below, it appears to be based on a misreading of Myers’s data.

Shaffer claims that Myers’s research on Indianapolis trials in the mid-1970s determined that “82 percent of the defendants in her sample did not testify,” and that she “found that defendants who testified were more likely to be convicted than those who did not.”169 As this stunning 82% number suggests, Shaffer misreads Myers’s study. (Recall the comparable figure for non-testifying defendants from the NCSC study was 50%; and the percentage from the famous but dated 1950s Kalven and Zeisel study is 18%).170 The variable in Myers’s study that Shaffer is interpreting as defendant testimony is labeled, “X 3 Testimony of Defendant and/or Accomplices.”171 Right away a problem is apparent: A variable intended to measure whether the defendant presented exculpatory testimony should not also include testimony from “[a]ccomplices.” Myers did find that the X 3 variable and two other measures correlate strongly with convictions: “[J]uries were more likely to convict if: the defendant or accomplice made a statement about his involvement in the crime or lack thereof (X 3 ); a weapon was recovered (X 6 ); and a large number of witnesses was specified in the indictment or information (X 7 ).”172 But as this excerpt indicates, the X 3 variable primarily captures not defendant testimony, but prosecution evidence, such as admissible pretrial statements of the defendant and accomplices to police.173 Myers describes the variable as a defendant (or accomplice) making a “statement,” codes it as “[n]one” or “[o]ne or more statements,” and includes it among other pro-prosecution evidentiary variables such as recovery of a weapon.174 Further, Myers fails to editorialize on the finding at any point.175 One would expect Myers to highlight and discuss an earth-shattering finding that defendant testimony typically backfires, strongly increasing the likelihood of conviction. It is not surprising, however, that Myers did not discuss the finding if she understood it to be mundane—that pretrial statements to police “about [the defendant’s] involvement in the crime” increase the likelihood of conviction.176 In sum, the finding Shaffer interprets as showing that defendants who testify are convicted more often says something very different. Shaffer and others who shy away from recommending that defendants testify based on Myers’s results are misreading her study.

B. The Ineffectiveness of Legal Doctrine Governing Defendant Testimony

The impacts of the silence and prior offender penalties described in the preceding sections reach far beyond trial tactics. As discussed in the next subparts, the empirical data summarized in Parts II through IV constitute a powerful indictment of the current legal framework.

One powerful implication of the existence of substantial silence and prior offender penalties is that legal doctrine designed to eliminate these penalties is ineffective. Two critical legal rules are in play: (1) jurors may not draw an adverse inference from the defendant’s refusal to testify;177 (2) when defendants do testify and are impeached with prior convictions, juries cannot consider the evidence as showing a criminal propensity.178 The empirical data analyzed above indicate that the legal system fails to effectively enforce both rules. Jurors are drawing adverse inferences from the defendant’s failure to testify—the “silence penalty.” And jurors improperly consider prior convictions offered solely as credibility impeachment as evidence of criminal propensities—the “prior offender penalty.” The penalties turn up consistently in experimental studies with mock jurors (see Parts II and III). They also appear to be powerful enough that they can be observed across a broad run of cases in data from real trials (see Part IV). To the extent the criminal justice system cares about enforcing its own rules, the data presented in this Article generate cause for concern. In this critical context, it appears that Justice Robert Jackson’s cynical critique rings true: “The naive assumption that prejudicial effects can be overcome by instructions to the jury all practicing lawyers know to be unmitigated fiction.”179

C. Distortions of Jury Factfinding

The data marshalled above also suggest that jurors indulge rough and often incorrect proxies for guilt that may interfere with their search for truth. The damage begins with the startling number of defendants who demand trial but decline to testify, depriving factfinders of a witness “who above all others may be in a position to meet the prosecution’s case.”180 When defendants do not testify, juries not only lose a testimonial resource, they are also tempted to draw an inference of guilt from that silence. Although prohibited by law, the inference may be warranted in certain circumstances—and thus not detrimental to the search for truth.181 But in many cases defendants decline to testify to avoid prior conviction impeachment. In that frequent scenario, jurors misread the silence signal; the defendant’s silence indeed suggests guilt, but it is guilt of a prior offense, not the offense for which he is on trial. Finally, when defendants do testify and are impeached with prior convictions, juries appear to slip into a form of propensity reasoning that causes them to overlook evidentiary weaknesses in the prosecution’s case.182

The dangers described above come into sharp relief in studies of convicted defendants who were later exonerated by DNA evidence. A comprehensive survey by John Blume found that 39% of later-exonerated defendants did not testify in their own trials; another study puts the number at 47%.183 These numbers are moderately lower than the generic 50% non-testifying rate in the NCSC study,184 suggesting that factual guilt is a factor, but not a powerful determinant of a defendant’s decision to testify. The factor that does seem determinative is a prior record. Blume reports that 91% of the later-exonerated defendants who did not testify “had prior convictions that potentially could have been used for impeachment purposes.”185 The fear of impeachment is well founded. Blume reports that “[i]n every single case in which a defendant with a prior record testified, the trial court permitted the prosecution to impeach the defendant with his or her prior convictions.”186

The stories of the exonerated defendants in Blume’s study parallel the themes presented in this Article. Legal rules inflate the number of silent defendants, and then distort jury factfinding by ensuring that no matter what course impeachable defendants take (testify or remain silent), juries receive a strong, if legally proscribed, pro-conviction signal. It is no surprise then that Blume reaches a conclusion that sadly resonates with the findings described above: “[T]he current rules of evidence contribute to wrongful convictions.”187

D. Incentivizing Guilty Pleas and Exacerbating Discriminatory Impacts

Two of the most troubling aspects of the modern criminal justice system are the sky-high prevalence of guilty pleas188 and the disproportionate impact of criminal punishment upon racial minorities.189 The historical data is unfortunately too sporadic to support definitive conclusions, but it hints that the parallel penalty dynamic plays a provocative and largely hidden role in each of these phenomena.

The historical link between the parallel penalties and guilty pleas is most provocative. The parallel penalties highlighted in this Article first became possible in the late 1800s as states enacted laws permitting defendant testimony. Legal historian George Fisher posits an early connection between defendant testimony rights and guilty pleas, noting that the “dramatic conversion to a plea bargaining regime” in Middlesex County, Massachusetts “started about a decade after defendants first began to take the witness stand.”190 Data from other state jurisdictions similarly support a trend of increased plea bargaining starting “in the latter part of the nineteenth century”—the same time defendant testimony laws emerged.191

But the parallel penalty dilemma may not have surfaced acutely with the onset of defendant testimony laws if the defendants standing trial were less likely to have a criminal record. In a time when jury trials more commonly concerned offenders with no official record, it would make sense—as Judge Ames predicted—for defendants to routinely take the witness stand. A defendant with a clean record can deftly sidestep the parallel penalty dilemma by testifying.

As the population of potential offenders with criminal records increases, the dynamic changes. When more and more defendants have a criminal record, fewer can avoid the parallel penalty dilemma by testifying. Foregoing trial altogether through a guilty plea becomes the most rational tactic.

Again, the historical evidence is by no means conclusive, but the apparently increasing prevalence of defendants with prior records, and decreasing prevalence of defendant testimony suggests the promise of future inquiries. The analysis begins with a comparison of the NCSC data to the other broad survey of American jury decision making, Kalven and Zeisel’s fabled empirical examination of American trials. In 1954–1955, Kalven and Zeisel surveyed criminal trials in a variety of jurisdictions and found that 47% of trial defendants had a criminal record and 82% testified.192 By 2000–2001, the NCSC study reports that 76% of defendants had a criminal record and only 50% of defendants testified.193 The samples do not match up precisely, of course, but the data hint that the pool of defendants who can (and do) avoid the parallel penalty dynamic by testifying is shrinking. The Bureau of Justice Statistics similarly reports that the percentage of arrestees with a criminal record is increasing over time.194 This makes intuitive sense in light of the ballooning population of former felons. The pool of potential defendants with a criminal record is deeper than it has been at any other point in history. In 1974, for example, 1.8 million American adults had previously served time in state or federal prison.195 By 2001, that number was 5.6 million.196

The parallel penalty-based pressure to plead guilty becomes particularly acute as more and more defendants face trial burdened with a prior record. These defendants can no longer cleanly avoid the silence penalty by testifying. And indeed guilty plea rates appear to have shot up once more in recent decades alongside the growing population of prior offenders. As a general matter, the proportion of guilty pleas increased in the past 35 years—the same time frame as the mass incarceration explosion.197 Causation is likely impossible to show as the variables are overlapping and interrelated. But the historical data we have fit an unsettling narrative. The parallel penalty dilemma makes trial unattractive for defendants with a criminal record, pushing these defendants to forego trial and plead guilty. And as defendants with criminal records increasingly become the norm rather than the exception, the parallel penalty dilemma inevitably contributes to a steady increase in guilty pleas and a corresponding decrease in trials.

There is another important piece to this story. The increasing prevalence of criminal records is not equally distributed among defendants.198 In the NCSC study, 71% of minority defendants had criminal records compared with 55% of white defendants.199 This disparity is consistent with general population trends. While in 2010 the percentage of the non-African American adult population with a prior felony conviction reached a high of 6%, that number was 25% for adult African Americans.200 This means that the pernicious effects of the parallel penalty dilemma disproportionately impact African-American defendants. The cycle is self-perpetuating. Every new conviction leads to a decreased likelihood of success in a subsequent trial and a stronger incentive to plead guilty.

VI. Conclusion

The Supreme Court and commentators’ celebration of the defendant’s right to testify is premature. Empirical evidence on the state of defendant testimony paints a picture more deserving of lamentation than glee. The landscape is so gloomy that it supports the 19th-century critics who counterintuitively proclaimed that defendants are better off when prohibited from testifying at trial.201 The right to testify may, in fact, play a supporting role in some of the most troubling aspects of modern American criminal justice, including the proliferation of guilty pleas and the disproportionate imprisonment of racial minorities.

The root of the problem is that the American criminal justice system has strayed from the presumption of innocence and the fabled insistence that “a defendant starts his life afresh when he stands before a jury, a prisoner at the bar.”202 The data summarized above suggest that juries consider trial silence to be incriminating, and draw legally improper criminal character inferences from prior convictions admitted as “impeachment.” As a result, the only defendants who truly enjoy a presumption of innocence at trial are the relatively few defendants without admissible prior crimes who elect to testify. By contrast, the bulk of criminal defendants, particularly those with a prior record, face a choice between two damaging options, a choice they can only avoid by forgoing trial and pleading guilty. In essence, the venerated right to testify may primarily operate to push prior offenders quickly through the justice system by limiting the attractiveness of trial and thereby incentivizing guilty pleas.

There are no easy solutions. A criminal justice system that relies on lay jurors will inevitably impose a “silence penalty” on defendants who refuse to testify.203 So long as American evidentiary rules simultaneously impose a “prior offender” penalty on defendants who do take the witness stand, these parallel penalties will predictably tilt the criminal justice scales toward conviction.

The critical point is that, for all its accolades, the modern right to testify is not just a lofty principle. It is part of a complex web of legal rules that, while vulnerable to criticism, have proven stubbornly resistant to change.204 Under the sway of those rules, the right to testify appears to be broadly harming criminal defendants and undermining the criminal justice system itself. In that light, the Supreme Court’s claim that there could be “no rational justification for prohibiting the sworn testimony of the accused”205 seems profoundly out of touch. There is certainly a rational basis for prohibiting sworn defendant testimony. It can be found in the data that reflect the stark realities of our flawed criminal justice system.