Most researchers do not approach survey data collection ab initio, but rather draw on "conventional wisdom", often encapsulated in existing textbooks or in what they have been taught at undergraduate or postgraduate level. We thought, therefore, that it would be appropriate to preface our review of empirical studies with a summary of current "expert opinion" and then to seek confirming or refuting evidence from primary research. Sources of expert opinion were key texts on survey methods (e.g. 1,5,13,40 ). These were identified through the personal and institutional libraries of the research team.
DatabasesIn our search for primary research studies, previous literature reviews and theoretical articles, we initially prioritised four electronic databases for searching:This review should be reviewed as a guide to best practice, not a definition of best practice. It is a decision aid, not a substitute for critical appraisal of the options available.