Bias in case-control studies

Case-control studies are largely used to explore differences between groups of individuals. They can identify potential risk factors associated with d isease, or they can investigate patient behaviour, such as why some people do not attend for services. As such, case-control studies are often used to generate or test hypotheses about causal factors. Nonetheless, bias is alw ays a danger in case-control studies, arising especially from the way in wh ich study samples are selected or from the collection of retrospective data . Confounding arise remains a problem. This short paper explores ways in wh ich such flaws can be uncovered in published studies.