“…Another major limitation frequently discussed by authors (n = 13 studies) concerned recall bias [13,21,25,26,30,31,33,35,38,39,48,73,76], as information on insurance membership (exposure) and health status and/or health-service use (outcomes of interest) was often collected at different time points, not always allowing a perfect match between the two. Authors of studies relying on secondary data often discussed limitations due to the nature of the secondary data [15,19,21,27,32,33,36,37,39,49,55,56,58,64,67,77], including lack of information on specific covariates to refine model estimation; impossibility of checking the quality and/or accuracy of the data; and for one study relying on medical charts, with large amounts of missing data [65]. Finally, only eight authors (four from quasi-experimental studies [22,61,62,73] and four from observational studies [37,38,59,76]), acknowledged the impossibility of establishing a causal link between insurance and outcomes of interest due to the crosssectional nature of the data being used.…”