In 2012 Coloradans approved Amendment 64, which legalized marijuana for recreational use, by a vote of 55 percent to 45 percent. Last February a Quinnipiac University poll found that 58 percent of Colorado voters supported that decision, while 38 percent opposed it and the rest weren't sure.

For prohibitionists determined to portray marijuana legalization in Colorado as a disaster, those poll results are inconvenient, since they indicate that public support for Amendment 64 was higher after more than a year of legal recreational sales and more than two years of legal possession and home cultivation than it was in 2012. Honest drug warriors would acknowledge the Quinnipiac numbers and perhaps try to balance them with other poll results. Dishonest drug warriors would do what the Rocky Mountain High Intensity Drug Trafficking Area (RMHIDTA) does in its new report on marijuana legalization: change the numbers.

The RMHIDTA, a federally supported task force dedicated to suppressing marijuana and other illegal drugs, claims only 50 percent of Colorado voters supported legalization in that Quinnipiac survey—eight points lower than the actual result. It also understates the 2012 vote for Amendment 64 by a point, but the comparison still supports the story that the task force wants to tell: The consequences of legalization in Colorado have been so bad that public support for the policy already has fallen.

Even assuming that the RMHIDTA's misrepresentation of the Quinnipiac survey was a mistake, the direction of the error is not random. You can be sure that if the report had overstated support for legalization by eight points, someone would have caught it before the text was finalized. Which underlines a point that should be obvious by now: Despite its pose as a dispassionate collector of facts, the RMHIDTA, which issued similar reports in 2013 and 2014, is committed to the position that legalization was a huge mistake, and every piece of information it presents is aimed at supporting that predetermined conclusion. So even when the task force does not simply make stuff up, it filters and slants the evidence to play up the purported costs of legalization while ignoring the benefits. Here are some examples of what I mean.

Drugged Driving

The report says "there was a 32 percent increase in marijuana-related traffic deaths" after legal recreational sales began in 2014 (emphasis in the original). Here is an interesting fact about "marijuana-related traffic deaths": They do not necessarily have anything to do with marijuana. The report uses this phrase to describe fatalities from accidents involving vehicle operators who "tested positive for marijuana," which could indicate the presence of inactive metabolites or THC levels so low that they had no impact on driving performance. A positive result does not mean a driver was impaired at the time of the crash, let alone that marijuana contributed to the accident.

As the report emphasizes in another chapter, adult marijuana use has been rising in Colorado since 2006. You would expect the percentage of drivers who "test positive for marijuana"—whether or not they are impaired and whether or not they get into accidents—to rise as well. It is not clear to what extent recent increases in what the RMHIDTA insists on calling "marijuana-related traffic deaths" are due to this population-wide trend and to what extent they are due to an increase in dangerously impaired drivers. The task force seems determined to obscure this crucial distinction.

Another factor to consider: The number of cannabinoid screens performed for law enforcement agencies in Colorado nearly tripled between 2009, when the medical marijuana industry started to take off, and 2014, the first year of legal recreational sales. That could reflect increased enforcement, increased stoned driving, or a combination of both. Likewise with last year's increases in marijuana-related DUID arrests by Denver police, which the RMHIDTA also cites as evidence that legalization has made the roads more dangerous.

Emergency Room Visits and Hospitalizations

In 2014, the report says, "there was a 29 percent increase in the number of marijuana-related emergency room visits" and "a 38 percent increase in the number of marijuana-related hospitalizations." Like "marijuana-related traffic deaths," "marijuana-related emergency room visits" and "marijuana-related hospitalizations" are not necessarily marijuana-related. As the report explains, these numbers, also known as "marijuana mentions," refer to patients whose marijuana use was determined by lab tests, self-reports, or "some other form of validation by the physician." The fact that a patient had used marijuana at some point "does not necessarily prove marijuana was the cause of the emergency admission or hospitalization."

It is therefore hard to know what to make of the increases highlighted by the report. They could be due to increased cannabis consumption, increased willingness to admit marijuana use, increased inquisitiveness by hospital staff, or some combination of those factors, none of which necessarily means that marijuana-related medical problems actually went up between 2013 and 2014, although it's possible they did.

Notably, the report includes a chart showing much smaller numbers for "marijuana-related" E.R. visits prior to 2013, even while cautioning that "inferences concerning trends…should not be made" because of "incomplete reporting" in 2011 and 2012. If the chart is misleading, why include it? Similarly, if "marijuana-related" does not mean what most people will assume it means, why use that term? The answer seems obvious: to strengthen the case against legalization, even if that means relying on spurious evidence.

Marijuana Exposures

The report says "marijuana-only" calls to the Rocky Mountain Poison and Drug Center "increased 72 percent" in 2014. Here the RMHIDTA is on firmer ground, since these calls really do involve marijuana and have increased in recent years. It is plausible that the increase, which has also been seen in Washington, is related to greater availability of marijuana edibles, first from dispensaries and later from recreational shops.

Most calls involve adults, although about 18 percent involve children 5 or younger. Whether people are mistaking edibles for ordinary food or taking bigger doses than they should have, these calls surely represent undesirable outcomes. But as usual, the RMHIDTA fails to put this troubling trend into perspective. Although the number of marijuana-only calls rose 148 percent between 2012 and 2014, last year's total, 151, still accounted for just 0.3 percent of the 50,000 or so calls that the poison control center received. The Colorado center does not report outcomes on its website. But according to data from the Washington Poison Center, just 3 percent of marijuana exposure cases involve a "major effect," and there have been no fatalities.

The RMHIDTA, which has a strong incentive to locate "marijuana-related" deaths in Colorado, describes one homicide, two apparent accidents, and three suicides. Marijuana's causal role in these six deaths is open to debate. But even if we take it as a given and include all 165 "traffic deaths related to marijuana" (which may or may not actually be related to marijuana) in 2013 and 2014, the death toll attributed to cannabis pales beside the thousands of alcohol-related deaths in Colorado during the same period.

Cannabis Consumption Trends

The RMHIDTA, which falsely claims that opponents of pot prohibition anticipate "no increase in use" after legalization, mistakenly counts rising consumption by adults as a cost of legalization. From an economic perspective, increased marijuana use should be counted as a benefit, since it means greater consumer satisfaction. Still, the task force is right that underage consumption is cause for concern.

It is not clear whether the loosening of marijuana prohibition in Colorado has led to an increase in consumption by teenagers. According to data from the National Survey on Drug Use and Health presented in the RMHIDTA report, the share of 12-to-17-year-olds in Colorado who admitted using marijuana in the previous month rose from 10.17 percent in 2009, when dispensaries began to proliferate, to 11.16 in 2013, the first year after Amendment 64 passed. That's an increase of about 10 percent. During the same period, the national average for past-month use rose only slightly, from 7.03 percent in 2009 to 7.15 percent in 2013. That's an increase of about 2 percent.

That comparison looks like evidence that Colorado's marijuana policies have increased underage consumption. But there was a similar divergence between Colorado and the national average before2009. In fact, the rate of past-month use by Colorado teenagers rose by 34 percent between 2006 and 2009, more than three times the increase between 2009 and 2013, while the national average rose by about 4 percent. That hardly fits the story the RMHIDTA wants to tell, according to which greater availability of marijuana from dispensaries, beginning in 2009, resulted in more adolescent pot smoking.

State-specific results from this survey are not available yet for 2014. It will take several more years of data to get a clearer sense of where underage consumption is headed in Colorado and how that trend compares to what is happening in states that have not legalized marijuana. While it is entirely possible that leakage from the legal market will boost underage consumption, that conclusion is clearly premature when we have no information about marijuana use by teenagers after recreational sales began.

The Parable of the Stoned Comedian

These are just a few examples of how the RMHIDTA systematically misrepresents what we know about the consequences of legalization. The more general problem is a confirmation bias that leads the task force to collect every scrap of information that reflects badly on legalization while ignoring anything that suggests a more positive (or less negative) view.

The RMHIDTA sifts through news reports for every mention of traffic accidents involving cannabis consumers but ignores the main conclusion of a landmark study by the National Highway Traffic Safety Administration, released last February, that found no association between marijuana use and car crashes. The task force treats negative trends, such as the 10 percent increase in underage marijuana use between 2009 and 2013, as evidence against legalization, but warns that positive trends, such as the 10 percent decline in marijuana-related drug treatment admissions during the same period, may not mean anything. The report never estimates the law enforcement savings, or even the decrease in marijuana arrests, that flow from legalization, but it finds space to fault state-licensed cannabusinesses for being victims of burglary, which it describes as "marijuana-related crime."

To show how truly horrific the consequences of legal marijuana can be, the report even devotes a paragraph to Ralphie May, a comedian "who was so high that he struggled to make it onto the stage," "had trouble finishing a joke," and "constantly lost his place." Meanwhile, the economic benefits of legalization, which you might think would rate at least as much space as the perils of cannabis-impaired comedy, get a sentence: "It will take years of data collection to complete an analysis of whether marijuana legalization is economically positive or an economic disaster." That's the RMHIDTA's idea of balance.

Addendum: Russ Belville and Christopher Ingraham point out another egregious misrepresentation in the report, this one lifted directly from an International Business Times article about the NHTSA crash-risk study. Page 30 of the report, toward the end of the chapter on impaired driving, quotes that article as saying "researchers found that marijuana users are 25 times more likely to be in an accident than those that did not use the drug." That is in fact what the article said, but it's not what the study said. As I explained last February, the study found that drivers who tested positive for active THC were 25 percent more likely to be involved in crashes. But once the researchers took sex, age, and race/ethnicity into account, the risk ratio shrank from 1.25 to 1.05 and was no longer statistically significant.

In other words, after the researchers adjusted for a few potentially confounding variables, there was no statistically significant association between marijuana and crash risk. The quote used in the report not only overstates the unadjusted risk ratio by a factor of 20; it gets the study's main finding completely wrong and suggests that marijuana impairs driving more than alcohol does, which is the opposite of the truth. As with the incorrect poll results, you could attribute this misrepresentation to carelessness: first by IBT reporter Amy Nordrum, then by the authors of the RMHIDTA report, who uncritically regurgitated her erroneous reporting. But this is a special kind of carelessness: the kind that desperately latches onto any assertion that seems to support the prohibitionist position, regardless of whether it happens to be true.

This article originally appeared at Forbes.com.