Explanation: preferences, motivations, and skills related to the behavior; (b) opportunities or constraints that make the behavior easier or more difficult to perform; and (c) incentives or disincentives that encourage or discourage the desired behavior relative to competing activities. Each of these factors is discussed in turn in this section. Much of the discussion is based on self-reported survey data and focus groups. Relative to observational surveys, self-reported data often provide unreliable estimates because of problems with recall or the well-established tendency of survey respondents to give socially desirable rather than completely truthful answers (see Chapter 2). Results from focus groups cannot be generalized to the population at large. Nevertheless, self-reports and focus groups are the only way to obtain insight into attitudes and motivations that help explain behavior. This type of information is particularly important because the determinants of physical activity behavior are not well understood.
