Groves and Couper (1998) and Harris-Kojetin and Tucker (1999) conducted similar time-series analyses. The latter study found that outside influences also played a role. The authors found evidence that changes in presidential approval, consumer sentiments regarding the economy, and the unemployment rate were reliably related to changes in refusal rates in the Current Population Survey.
Survey methodologists have proposed several theories to explain why people participate in surveys. According to Goyder et al. (2006), the development of a theory of survey response has centered on several key themes: People respond to surveys when they conclude that the rewards outweigh the costs; societal factors, such as social disorganization or high crime rates, cause some respondents to refuse; different sociodemographic groups are more or less prone to take part in surveys; factors in the survey setting may influence a near-instantaneous decision; there is growing concern over intrusions on people’s time and privacy; the growth in the number of surveys has led to stronger attitudes about surveys in general, apart from topic; interviewers play a key role in gaining cooperation, especially in face-to-face surveys; the topic salience plays a role; participation is partly an emotional decision; response propensities can vary by mode of data collection; and there is a random component to these decisions. These ideas are captured to one degree or another in three main theories—social capital theory, leverage–saliency theory, and social exchange theory—which are summarized below.
Social Capital Theory
Social capital theory may help to explain the social and psychological underpinnings of the interpersonal relationships that promote trust and cooperation and thus promote the willingness to respond to surveys. According to Robert Putnam, who popularized this theory in his work (1995, 2001), social capital refers to the trust that people gain through productive interaction and that leads to cooperation. The cooperation is manifested in community networks, civic engagement, local civic identity, reciprocity, and trust in the community. Social capital can be measured in the prevalence of community organizations. The decline in association memberships in recent years is associated with less confidence in public institutions.
On an individual level, social capital is gained through education, which provides greater networking opportunities (Heyneman, 2000). Lower socioeconomic status is associated with reduced levels of trust and cooperative behavior (Letki, 2006). Other individual-level attributes affect the build-up