“…This approach produces a valid inference by using a working model between responses and covariates, regardless of whether the working model is correct or not. To consider the regression adjustment for baseline covariates in addition to stratification covariates, stratum-common estimators and stratum-specific estimators have been developed, mainly for the case in which the allocation ratios are the same across strata (Liu et al, 2023;Ma et al, 2022;Ye et al, 2022aYe et al, , 2022b. However, little attention has been paid to the case in which the allocation ratios are different across strata, especially when additional baseline covariates are included, although different allocation ratios are commonly used in practice and are more flexible (Angrist et al, 2014;Chong et al, 2016).…”