ABSTRACT
This chapter describes several indirect sources of data: (1) physical traces, such as fingerprints and broken windows; (2) virtual (electronic) traces, such as data from mobility patterns stored on smartphones; (3) contemporary records such as magazines, music, and Internet websites; and (4) archival and historical records like records of gravestone inscriptions and church records. Excerpts from published research illustrate each type of source. The chapter also describes two indirect data collection methods: (a) unobtrusive observation and (b) content analysis. Indirect methods produce data not available from other sources, and sometimes produce more valid data than survey data, because indirect methods avoid contamination from respondent reactions or from inaccurate recall. But issues of validity can be important limitations, particularly with historical data, for which coverage may be incomplete, with limited sources for checking accuracy. Early evidence suggests that virtual trace data could help researchers obtain more representative samples producing generalizable findings about people’s day-to-day behavioral tendencies. Such data could also provide more valid data than from surveys or observations by avoiding contamination of memory limitations or socially desirable responses. Combining data from several methods to study the same phenomenon remains perhaps the best approach to obtain more valid and generalizable information.
