De praktijk van systematische reviews. VI. Zoeken, selecteren en methodologisch beoordelen van etiologisch onderzoek

-Optimal search strategies for the identification of publications on aetiological research are currently not available.

-The definition of adequate selection criteria is necessary to limit the harvest to a relevant and homogeneous set of publications. Yet, the harvest should be high in order to prevent many relevant papers being missed.

-The methodological assessment of aetiological research should be aimed at the estimation of the presence of selection bias, information bias, and confounding.

-Important items of the methodological assessment are independent and standardised assessment of exposure and outcome, high response rate, no selective dropout, and adjustment for confounding in the analysis.