Dwalingen in de methodologie. VIII. Pilotonderzoeken: Zin en onzin

- A pilot study is often performed before the start of a large study. Its aim is improving the methodological quality and evaluating the feasibility. - The results of a pilot study are also often used to gain an impression of the efficacy of an intervention. For this purpose a pilot is absolutely unsuited. - However, the estimate of the effect of an intervention in small studies such as pilot studies is determined to a large extent by chance. When conducting small studies the chance of publication bias is large. - Small studies of adequate methodological quality should be published, whether the results are positive or negative, significant or non- significant, because combination in a later cumulative meta-analysis may lead to sufficient power to assess the efficacy of an experimental intervention.