Can propensity score matching replace randomized controlled trials?

Table 3 Possible matching methods utilized in propensity score matching studies

Matching method	Indication
One-to-one	This method matches each treated unit with one control unit that has the closest propensity score. This method is simple and intuitive, but it may discard some units that are not matched
One-to-many	This method matches each treated unit with more than one control unit that has similar propensity scores. This method can increase the sample size and precision, but it may also introduce more bias due to imperfect matches
Nearest neighbor	This method matches each treated unit with the control unit that has the nearest propensity score, within a specified caliper or threshold. This method can reduce bias by excluding poor matches, but it may also reduce efficiency by excluding good matches
Caliper	This method matches each treated unit with the control unit that has the propensity score within a specified range or distance. This method can ensure a high degree of similarity between the matched pairs, but it may also result in a loss of observations if the caliper is too narrow
Stratification	This method divides the propensity score distribution into a number of strata or intervals, and then compares the outcomes of the treated and control units within each stratum. This method can balance the covariates across the strata, but it may also produce heterogeneous treatment effects across the strata