Sampling in research on interpersonal aggression.

The aim of this study was to investigate the usefulness of convenience samples in research on interpersonal aggression among adults. It was hypothesised that convenience sampled targets of aggression differs from targets in general with regards to both demographic characteristics and degree of aggression exposed to. A convenience sample comprising support-seeking targets of workplace bullying was compared with a representative sample of Norwegian targets of bullying. The results showed that the two samples differed significantly on all demographic variables investigated, except gender. A far higher percentage of the convenience sample had blown the whistle on illegal, immoral or illegitimate practice at their workplace, whereas they also reported significantly more frequent and more intense exposure to aggression. The findings confirm that convenience samples have low external validity when generalising to the general population. Such samples should therefore mainly be used to investigate tendencies in, and the phenomenology of, interpersonal aggression, in studies where generalisability is not the principal objective. Copyright 2007 Wiley-Liss, Inc.