Validity of Cross-National Research Using Unrepresentative Convenience Samples

Abstract

Many multi-nation surveys use samples that are not representative of the nations compared. Examples include surveys of students or families of students in different nations (Straus 1968; Straus and Straus 1968), of nurses (Glazer and Gyurak 2008), and of residents of the largest city in each nation in the study (Lynch 2008). None of these studies used nationally representative samples, yet they draw conclusions about differences between nations. This article provides empirical data on whether valid cross-national conclusions can be made using these types of unrepresentative samples when the samples are drawn from the same subpopulations in each country and using similar study designs. It reports empirical tests of the cross-national validity of data obtained for a 32-nation study using convenience samples of university students – the International Dating Violence Study or IDVS. The IDVS sample is not representative of the 32 nations because university students differ from the general population in important ways. In addition, because the sample consisted of students in classes taught by the member of a research consortium in that nation and in classes where other teachers permitted the questionnaire to be administered, the students in IDVS are not random samples of students in their nation, or even of students in their own university. Members of the consortium conducting the study administered the study questionnaire in enough of their own and classes taught by others.