Partial support for this research was provided by National Science Foundation grants BNS-8509673 and SES-8715564 awarded to the first and second authors, respectively, and by a grant from the Carnegie Council on Adolescent Development to the second author. We are grateful to Brad Bell for his assistance in data collection and to Lita Furby for her comments on earlier drafts of this paper, and to Rosa Lio for manuscript preparation.
The Psychology of Contraceptive Surprises: Cumulative Risk and Contraceptive Effectiveness1
Article first published online: 31 JUL 2006
Journal of Applied Social Psychology
Volume 20, Issue 5, pages 385–403, March 1990
How to Cite
Shaklee, H. and Fischhoff, B. (1990), The Psychology of Contraceptive Surprises: Cumulative Risk and Contraceptive Effectiveness. Journal of Applied Social Psychology, 20: 385–403. doi: 10.1111/j.1559-1816.1990.tb00418.x
- Issue published online: 31 JUL 2006
- Article first published online: 31 JUL 2006
Two studies investigated young adults' expectations about long-term contraceptive effectiveness. Subjects were told about five hypothetical methods of contraception varying in reported effectiveness, which was expressed in terms of the likelihood of avoiding pregnancy for base periods of 1 year (Experiment 1), 5 years, or 10 years (Experiment 2) of use. For each method, subjects estimated the likelihood that a woman would avoid pregnancy while using it for periods ranging from 1 month to 15 years, and then rated how satisfied they would be with it. For nearly half of the subjects, estimates of cumulative effectiveness did not decline as time period increased. Those subjects who did realize that cumulative effectiveness declined over time estimated rates that declined too slowly for methods of modest and low reliability, and at rates that were too similar for methods differing in effectiveness. Subjects were overly optimistic about effectiveness for time periods longer than the base period, and overly pessimistic about effectiveness for shorter time periods. Not surprisingly given these results, subjects expressed more satisfaction when a method's effectiveness was expressed in shorter base periods. Such faulty understanding of the long-term implications of contraceptive effectiveness information may undermine people's abilities to make informed contraceptive choices.