Sample Characteristics

Completed surveys were received from 771 of the 978 invited trial participants (79%) and included 350 mailed surveys and 421 surveys completed in the clinic (Section 1 in the Supplementary Appendix). Respondents were fairly evenly distributed across the three academic medical centers (33%, 27%, and 40%) and were drawn from 119 different trials. Percentages based on the 771 respondents have a 95% confidence interval no wider than ±3.6 percentage points.

Table 1. Table 1. Sample Characteristics as Reported in the Survey.

Table 1, and Table S6 in the Supplementary Appendix, show the characteristics of the sample. Within the previous 2 years, 42% of the respondents had participated in a clinical trial as a person with the health condition being studied, 55% as a healthy volunteer or person at risk for the studied health condition, and 3% as both. The two most common topics studied in the trials were diabetes and issues related to nutrition, weight, and vitamin supplementation. A total of 90% of respondents were trial participants themselves, and 7% were parents of participants. More than 94% of the respondents reported having had positive experiences as clinical trial participants. Half were motivated to participate in the trial by the prospect of a health benefit, 33% by altruism, and 16% by other factors.

Perceived Risks of Data Sharing

Figure 1. Figure 1. Level of Concern about Potential Consequences of Data Sharing. Shown are the responses to an item worded as “How concerned are you about the following potential consequences of sharing anonymous, individual clinical trial data?” Numbers were rounded to the nearest tenth. The accuracy (95% confidence interval) of the percentages close to 50% is ±3.6 percentage points, diminishing to ±2.2 percentage points for percentages close to 10%.

For 9 of 11 potential consequences of data sharing, less than 10% of the respondents said they were “very concerned” and less than one third were “very” or “somewhat” concerned about the risk (Figure 1). A total of 20% to 26% of the respondents were very or somewhat concerned about discrimination, reidentification, and exploitation of data for profit. Respondents were more concerned that data sharing could deter people from enrolling in clinical trials (37%), that companies might use the information for marketing purposes (34%), or that their data could be stolen (30%). Asked to select the most important potential risk, respondents expressed divergent views, with the most common choices being that the information might be stolen (15%) or used for marketing purposes (11%) and that others might be more reluctant to enroll in clinical trials if they knew their data would be shared (10%) (Table S7 in the Supplementary Appendix).

Perceived Benefits of Data Sharing

Figure 2. Figure 2. Perceived Benefits of Data Sharing. Shown are the responses to an item worded as “How much do you think sharing anonymous, individual clinical trial data can ….” Numbers were rounded to the nearest tenth. The accuracy (95% confidence interval) of percentages close to 50% is ±3.6 percentage points, diminishing to ±2.2 percentage points for percentages close to 10%.

Strong majorities of respondents (67% to 82%) believed that data sharing would yield “a great deal” or “a lot” of several benefits (Figure 2). In contrast, 43% believed it would help lawyers prove their case in product liability lawsuits. When respondents were asked to choose the most important benefit of data sharing, the most popular choices were making sure people’s participation in clinical trials leads to the most scientific benefit possible (18%) and helping to get answers to scientific questions faster (17%) (Table S8 in the Supplementary Appendix). More than 85% of respondents expected that scientists in universities and other not-for-profit settings would benefit “a great deal” or “a lot” from data sharing; 81% of respondents had this expectation for physicians taking care of patients, 79% for companies developing medical products, and 72% for patients (Table S9 in the Supplementary Appendix)

Overall Support for Data Sharing

In response to a question at the end of the survey, 82% of respondents indicated that they perceived that the benefits of data sharing outweighed the negative aspects, 8% felt the negative aspects outweighed the benefits, and 10% considered them equal (Table S10 in the Supplementary Appendix).

Table 2. Table 2. Willingness of Clinical Trial Participants to Share Their Data, According to Type of Use and Recipient.

A total of 93% of respondents said they were very (69%) or moderately (24%) likely to allow their clinical trial data to be shared with scientists in universities and other not-for-profit organizations (Table 2), and 4% were very or somewhat unlikely to share. Although respondents had less trust in drug companies (18% trusted them a great deal or a lot) and health insurance companies (15%) than in universities (63%), 82% reported that they would be very or somewhat willing to share data with for-profit companies, whereas 8% were very or somewhat unwilling to share (Table 2, and Table S11 in the Supplementary Appendix).

Willingness to share data varied little according to the purpose for which it would be used — with the exception of its use in lawsuits, although a majority of respondents were still willing to share even for that purpose (Table 2). No appreciable differences were found between uses that did and uses that did not benefit the participant directly or between uses for verifying previous research results and uses for making new discoveries.

Among the write-in comments, the most dominant theme was the need to help others as much as possible. Many commenters expressed confidence in the deidentification of data. Several urged greater cooperation and less competition among scientists.

Predictors of Attitudes

In multivariable modeling, the likelihood that a respondent would feel that the negative aspects of data sharing outweighed the benefits was significantly higher among those who felt that other people generally could not be trusted (odds ratio, 2.3; 95% confidence interval [CI], 1.2 to 4.6) and among those who were concerned about the risk of reidentification (odds ratio, 2.4; 95% CI, 1.2 to 4.5) or about information theft (odds ratio, 2.2; 95% CI, 1.2 to 4.1) (Section 4 in the Supplementary Appendix). The only other significant predictor was having a college degree, which was associated with a lower likelihood of feeling that the negative aspects of data sharing outweighed the benefits (odds ratio, 0.27; 95% CI, 0.2 to 0.5).

A low level of trust in people was also a significant predictor of being somewhat or very unlikely to share one’s own data with scientists in not-for-profit contexts (odds ratio, 3.7; 95% CI, 1.6 to 8.3) or drug companies (odds ratio, 2.5; 95% CI, 1.3 to 4.8). Low trust in drug companies was a significant predictor of unwillingness to share data with drug-company scientists (odds ratio, 2.4; 95% CI, 1.4 to 4.2). Having a college degree was associated with a significantly lower likelihood of refusing to share data with not-for-profit scientists (odds ratio, 0.28; 95% CI, 0.10 to 0.78).