Number of visits and duration of surveys

Using data from European Social Survey 2002 I attempt to determine two questions. First, what are basic determinants of availability of respondents as defined in terms of number of visits to make interview. Second, to what extent responses are affected by date of interview in time trajectory of the research. One may assume that significant relationships between date of interview and responses would indicate systematic error resulting from effect of the context of interview related to time. My analysis is based on the Polish data. According to main findings, basic impediments of availability of respondents included: higher education, residence in bigger city, and younger category of age. Conversely, relatively most accessible are: unemployed, countryside dwellers, and lower non-manual workers. This analysis show also that date of interview exerts significant effect on responses. Key words: duration of interview, number of visits, availability of respondents, systematic error, non-responses