[Considerations on what we can (and what we should not) ask to registries]

This article presents a summary of the discussion which took place during the works of PRIER II in the session dedicated to the methodology of registries. Following a thorough analysis of the possible methods and the limits which deal with the collection of clinical data through the registries, the different points of view were compared, perhaps the most relevant, related to this activity. All this has been done by taking advantage by the possibility to observe aspects from different points of view. In particular, the exercise considered those who have to deal with the methodological aspects of the registries as an operator of public health or as a private operator who creates services for companies. The final goal, again, was to line up a few essential points accompanied by reasoning and comments useful to anyone who wants to address the issue of registries from the methodological point of view.