To protect children and adolescents against and inform parents about harmful media content, media ratings show whether a media product's content is harmful for minors below a given age. In this research project, we performed a series of studies into the effectiveness of media ratings in the Netherlands. We especially focused on the moment at which industry meets the public (the transaction moment) and placed special emphasis on the degree of compliance with the applicable rules (does the media industry comply with media ratings?). Based on a literature study and document analysis, several parameters for effectiveness were identified. These were then empirically investigated using a wide variety of communication research methods. Methodological issues concerning all five research methods studied will be addressed.