Objective To compare propensity score(PS)matching and disease risk score(DRS)matching in the scenarios of good PS overlap and poor PS overlap,and to investigate the optimal caliper width for DRS matching.Methods According to the different proportions of the test group and events as well as the different PS overlap situations,6 scenarios were simulated to compare the balance of covariables and the bias before and after PS matching or DRS matching,followed by analysis of an actual case.Results In the scenarios with good PS overlap,the DRS overlap was also good,and PS matching was more accurate than DRS matching.The optimal caliper width was found to be 10％-20％of the PS standard deviation(SD)for PS matching,and the relativeoptimal caliper width was 0.5％of the DRS SD for DRS matching.In the scenarios with poor PS overlap,the DRS overlap was also poor,but the DRS matching was more accurate than PS matching.The optimal caliper width was found to be 15％-20％of the DRS SD.In addition,the improvement on the balance of covariates was consistent with the estimation bias of treatment effect.Conclusions When the overlap of PS is good,PS matching is preferred;when the overlap of PS is poor,DRS matching can be selected,and the optimal caliper width is 15％-20％of the DRS SD.In practical application,the control effect for measured a confounder can be evaluated according to the improvement on the covariable balance between groups.
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