The Effectiveness of a Primer to Help People Understand Risk

Two Randomized Trials in Distinct Populations

20 February 2007 | Volume 146 Issue 4 | Pages 256-265

Background: People need basic data interpretation skills to understand health risks and to weigh the harms and benefits of actions meant to reduce those risks. Although many studies document problems with understanding risk information, few assess ways to teach interpretation skills.

Objective: To see whether a general education primer improves patients' medical data interpretation skills.

Design: Two randomized, controlled trials done in populations with high and low socioeconomic status (SES).

Setting: The high SES trial included persons who attended a public lecture series at Dartmouth Medical School, Hanover, New Hampshire; and the low SES trial included veterans and their families from the waiting areas at the White River Junction Veterans Affairs Medical Center, White River Junction, Vermont.

Participants: 334 adults in the high SES trial and 221 veterans and their families in the low SES trial were enrolled from October 2004 to August 2005. Completion rates for the primer and control groups in each trial were 95% versus 98% (high SES) and 85% versus 96% (low SES).

Intervention: The intervention in the primer groups was an educational booklet specifically developed to teach people the skills needed to understand risk. The control groups received a general health booklet developed by the U.S. Department of Health and Human Services Agency for Health Care Research and Quality.

Measurements: Score on a medical data interpretation test, a previously validated 100-point scale, in which 75 points or more is considered "passing." Secondary outcomes included 2 other 100-point validated scores (interest and confidence in interpreting medical statistics) and participants' ratings of the booklet's usefulness.

Results: In the high SES trial, 74% of participants in the primer group received a "passing grade" on the medical data interpretation test versus 56% in the control group (P = 0.001). Mean scores were 81 and 75, respectively (P = 0.0006). In the low SES trial, 44% versus 26% "passed" (P = 0.010): Mean scores were 69 and 62 in the primer and control groups, respectively (P = 0.008). The primer also significantly increased interest in medical statistics by 6 points in the high SES trial (a 4-point increase vs. a 2-point decrease from baseline) (P = 0.004) and by 8 points in the low SES trial (a 6-point increase vs. a 2-point decrease from baseline) (P = 0.004) compared with the control booklet. The primer, however, did not improve participants' confidence in interpreting medical statistics beyond the control booklet (a 2-point vs. a 4-point increase in the high SES trial [P = 0.36] and a 2-point versus a 6-point increase in the low SES trial [P = 0.166]). The primer was rated highly: 91% of participants in the high SES trial found it "helpful" or "very helpful," as did 95% of participants in the low SES trial.

Limitations: The primarily male low SES sample and the primarily female high SES sample limits generalizability. The authors did not assess whether better data interpretation skills improved decision-making.

Conclusion: The primer improved medical data interpretation skills in people with high and low SES.

ClinicalTrials.gov registration number: NCT00380432.

Editors' Notes Context Educational materials aimed at improving people's ability to understand information about risk are scarce. Contribution In 2 trials, adults with high or low socioeconomic status (SES) were randomly assigned to receive a primer about understanding risk or a general health booklet. In both SES groups, adults receiving the primer more often passed a medical data interpretation test than did those receiving the general health booklet. They also expressed greater interest in medical statistics but not greater confidence in interpreting statistics, and most rated the primer helpful or very helpful. Cautions The authors did not examine whether improved data interpretation skills affected decision-making. —The Editors

 

Author and Article Information

From the Veterans Affairs Outcomes Group, White River Junction, Vermont, and the Center for the Evaluative Clinical Sciences, Dartmouth Medical School, Hanover, New Hampshire.

Disclaimer: The views expressed herein do not necessarily represent the views of the Department of Veterans Affairs or the U.S. government.

Note: The first two authors contributed equally to the creation of this manuscript. The order of authorship is arbitrary.

Acknowledgments: The authors thank Donald St. Germaine, MD, and Wendy Murphy for their assistance in recruiting Dartmouth Community Medical School alumni; Jennifer A. Snide for technical assistance; and Baruch Fischhoff, PhD, and Wylie Burke, MD, PhD, for helpful comments on earlier drafts of the primer.

Grant Support: Drs. Woloshin and Schwartz are supported by Robert Wood Johnson Generalist Faculty Scholars Awards and receive infrastructure support from a Research Enhancement Award from the Department of Veterans Affairs. The study was supported by a grant from the National Cancer Institute (R01CA104721).

Potential Financial Conflicts of Interest: None disclosed.

Requests for Single Reprints: Lisa M. Schwartz, MD, MS, VA Outcomes Group (11B), Department of Veterans Affairs Medical Center, White River Junction, VT 05009; e-mail, Lisa.schwartz{at}dartmouth.edu.

Current Author Addresses: Drs. Woloshin, Schwartz, and Welch: VA Outcomes Group (11B), Department of Veterans Affairs Medical Center, White River Junction, VT 05009.

Author Contributions: Conception and design: S. Woloshin, L.M. Schwartz, H.G. Welch.

Analysis and interpretation of the data: S. Woloshin, L.M. Schwartz, H.G. Welch.

Drafting of the article: S. Woloshin, L.M. Schwartz, H.G. Welch.

Critical revision of the article for important intellectual content: S. Woloshin, L.M. Schwartz.

Final approval of the article: S. Woloshin, L.M. Schwartz, H.G. Welch.

Provision of study materials or patients: S. Woloshin, L.M. Schwartz.

Statistical expertise: S. Woloshin, L.M. Schwartz.

Obtaining of funding: S. Woloshin, L.M. Schwartz.

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