Participation in epidemiology studies

There are two major reasons to maximize participation in an epidemiological study. Firstly, low participation can lead to bias and secondly, inadequate numbers recruited can limit the power of the study. All other things being equal, lower participation will increase the influence of non-response bias in a study. However, it should be noted that even in studies with high participation there exists a possibility of selection bias if non-participants are markedly different from participants in aspects that are key to the conditions being studied. There are several ways of boosting participation which should be embedded into the study design from the start, since chasing up to increase participation is resource-expensive.