Samenvatting
This paper discusses nine criteria that can be used to assess whether the effects attributed to road safety treatments in studies evaluating the effects of such treatments are causal or merely reflect randomness, confounding or non-causal statistical association. The criteria are to a major extent based on similar criteria developed in epidemiology to assess the causality of factors associated with diseases. These criteria can be used to assess the quality of road safety evaluation studies. The more criteria a study satisfies, the better is its quality. Use of the criteria is illustrated by means of examples. For the covering abstract see ITRD E138952. This paper is available from http://www.ictct.org/workshops/06-Minsk/Elvik.pdf.