Scientific progress is severely impeded if experimental measurements are not reproducible. Materials chemistry and related fields commonly report new materials with limited attention paid to reproducibility. Here, we describe methods that are well suited to assessing reproducibility in these fields via retrospective analysis of reported data. This concept is illustrated by an exhaustive analysis of a topic that has been the focus of thousands of published studies, gas adsorption in metal-organic framework (MOF) materials. We show that for the well-studied case of CO2 adsorption there are only 15 of the thousands of known MOFs for which enough experiments have been reported to allow strong conclusions to be drawn about the reproducibility of these measurements. Our results have immediate implications for the characterization of gas adsorption in porous materials but, more importantly, demonstrate an approach to assessing reproducibility that will be widely applicable in materials chemistry.