If you cheated on your spouse, would you admit it to a researcher? That question is one of the biggest challenges in the scientific study of marriage. Surveys conducted in person are likely to underestimate the real rate of adultery, because people are reluctant to admit such behavior. In a study published last summer, researchers surveyed 4,884 married women, using face-to-face interviews and anonymous computer questionnaires. In the interviews, only 1 percent of women said they had been unfaithful to their husbands in the past year; on the computer questionnaire, more than 6 percent did. At the same time, experts say that surveys appearing in sources like women’s magazines may overstate the adultery rate, because they suffer from what pollsters call selection bias: the respondents select themselves and may be more likely to report infidelity. But a handful of new studies suggest surprising changes in the marital landscape. Infidelity appears to be on the rise, particularly among older men and young couples. Notably, women appear to be closing the adultery gap: younger women appear to be cheating on their spouses nearly as often as men. New York Times, October 28, 2008