News Release

Monday, June 13, 2011

NIH-funded study uses planning prompts to enhance vaccination rates

A nudge can make all the difference.

We all have good intentions, but sometimes we need a nudge to turn those intentions into actions. According to a new study, encouraging people to write down the date and time when they plan to get their flu shot increased the number of people who were vaccinated.

The results of the randomized behavioral intervention appear in the June 13 online issue of the Proceedings of the National Academy of Sciences. The research was supported by the National Institute on Aging (NIA), part of the National Institutes of Health.

The researchers analyzed the effects of different reminder mailings sent to those employees of a large utility firm who were considered at risk for the flu. All eligible employees received one of three possible reminder mailings that listed the times and locations of free on-site flu vaccination clinics. Past research has shown that reminder mailings are among the most cost-effective ways to increase patient compliance. In this case, those who were encouraged further to write down both the date and time when they planned to receive the vaccination had a significantly higher rate of vaccination than those who received the mailing listing only the times and locations of the clinics.

“These findings have the potential to strengthen efforts to improve public health by increasing vaccination rates, as well as other constructive health activities,” said NIA Director Richard J. Hodes, M.D. “This study shows that positive health effects can be achieved at a very low cost.”

Reminder mailings were sent to 3,272 employees who were age 50 or older or had chronic health conditions that increase the risk of flu-related complications. The control group received a mailing listing the times and locations of vaccination clinics. The first treatment group received a mailing that also prompted them to write down the date they planned to be vaccinated; the second treatment group received a mailing that prompted them to write down the date and time they planned to be vaccinated.

The overall vaccination rate among study participants in the control group was 33.1 percent. The rate in the date-plan group increased by 1.5 percentage points relative to the control group. The date-and-time-plan group had a 4.2 percentage point increase relative to the control group.

“Converting good intentions into real behavior has proven very difficult. Most people know what they need to do to improve their health and have excellent intentions, but there is a huge gap between their intentions and what they then do,” noted Richard Suzman, Ph.D., director of NIA’s Division of Behavioral and Social Research, which funded the study.

Suzman noted that NIH has been focusing on several initiatives on the science of behavior change that may lead to cost-effective approaches. “In this study, the research expands the application of behavioral economics to the health care setting, focusing on individual models of decision-making and resulting in a meaningful improvement at zero cost. It suggests that making a very concrete plan to take a particular action can help turn the intention into action,” he said.

“Interestingly, the planning prompt was most effective among employees for whom on-site flu shots were only offered on a single day,” said lead author Katherine L. Milkman, Ph.D., of the Wharton School at the University of Pennsylvania in Philadelphia. “For this group, forgetting to attend an on-site clinic once would mean forgoing the opportunity altogether. Prompting these employees to write the date and time when they intended to receive their shot increased compliance by 27 percent.”

The research was funded through grants from the NIA to investigators at the Roybal Center for Behavior Change in Health and Savings at the National Bureau of Economic Research (NBER) in Cambridge, Mass. NBER provided support to investigators at participating institutions. The goal of the 13 Edward R. Roybal Centers for Translation Research in the Behavioral and Social Sciences of Aging is to move promising social and behavioral research findings out of the laboratory and into programs and practices that will improve the lives of older people and help society adapt to an aging population.

The NIA leads the federal government effort conducting and supporting research on aging and the health and well-being of older people. The Institute’s broad scientific program seeks to understand the nature of aging and to extend the healthy, active years of life. For more information on research, aging, and health, go to

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit

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Using Implementation Intentions Prompts to Enhance Influenza Vaccination Rates. Katherine L. Milkman, John Beshears, James J. Choi, David Laibson, Brigitte C. Madrian. Proceedings of the National Academy of Sciences. Epub June 13, 2011.