'I don't know' in public opinion surveys in China: Individual and contextual causes of item non-response

Why do some people say 'I don't know', 'I have no opinion', or simply refuse to say anything in a public opinion survey? The Western literature on public opinion research suggests two major types of causal factors for the non-response: the respondent's individual characteristics ("e.g. age, education, and occupation), and the survey's contextual characteristics (e.g. the length of the survey, the nature of the question, and the setting of the interview). The emphasis, however, has been on the individual factors. This study applies these theoretical predictions to a pool of 14 survey data collected in China during the 1980s. The results show that both the individual and contextual factors are equally important in determining the occurrence of non-response. In particular, farmer respondents, questions involved a politically sensitive topic, and surveys sponsored by a government agency are more likely to cause 'I don't know' answers. Interaction analysis provides some preliminary evidence to suggest that lack of cognitive ability may be a primary source of non-response on knowledge-related questions while fear of political consequences may be responsible for non-response on political sensitive questions. Based on the findings, we discuss the implications for analysis and interpretation of Chinese survey data.