Introduction: Assessing the quality of RCTs included in a review is important. Firstly, because variation in quality can explain differences in the results. Secondly, because when the methodology of the RCTs included in the review is weak, the conclusions of the review cannot be very strong. It is also needed that experts achieve agreement on quality assessment, especially where the quality of individual studies is incorporated in systematic reviews and meta-analyses. Therefore we aimed at developing a universal criteria list as a minimum reference standard to be used in future systematic reviews.

Objective: To develop a consensus criteria list to assess the methodological quality of trials in systematic reviews.

Methods: The Delphi method is a consensus method using written questionnaires. The participants remain anonymous and receive feedback after each round about the answers and arguments of other participants.

Results: The procedure started with 33 participants representing different points of view on quality assessment. The participants are clinicians, epidemiologists and statisticians. Starting from 206 quality items we want to come to a hierarchy of importance and end up with a short list. At least 3 or 4 Delphi-rounds are necessary to obtain consensus. The resulting Delphi criteria list will be presented.

Discussion: A consensus definition about 'quality' will be derived from the results. There are differences in opinion between statisticians on the one hand and clinicians/epidemiologists on the other. Practical implications will also be presented at the congress.