ABSTRACT
This chapter defines secondary data and indicates the kinds of secondary data available to researchers and how to work with such data. Using secondary data has many attractions, and this chapter indicates these (e.g. in scope, size, quality, efficiency, access). Similarly, secondary data present many challenges: they are not gathered for the purpose of research or are gathered for different purposes, so the researcher has to contend with many challenges in using them. This chapter sets out several such challenges (e.g. ethical issues; poor fit to present purposes; incompleteness, poor coverage and selectivity; differences of definitions; non-neutral data; limited information on data collection; restrictions on access and usage; and how they can be addressed). Researchers working with secondary data must ensure that their present purposes are sufficiently compatible with the original data sets on which they are working and that the data lend themselves fairly to the kinds of analysis being used and purposes for which they are being used. The chapter indicates how to address these matters, what challenges may arise and how to address them, and it provides examples of how to proceed here, with plentiful practical advice.
