Methodological index for non‐randomized studies (MINORS): development and validation of a new instrument

Background:  Because of specific methodological difficulties in conducting randomized trials, surgical research remains dependent predominantly on observational or non‐randomized studies. Few validated instruments are available to determine the methodological quality of such studies either from the reader's perspective or for the purpose of meta‐analysis. The aim of the present study was to develop and validate such an instrument.