If there is selection bias, matching estimators are not robust (Rosenbaum 2002).
If there is a hidden bias, matching estimators are not robust (Rosenbaum 2002).
To prevent bias, matching placebo tablets, which were identical in appearance, taste, and odor, were used.
To prevent classification and observer bias, matching of ED visits was completed with the investigator (LO) blinded to the ED diagnosis and visit details.
The pattern of this adjustment was virgin-biased, matching the theoretical prediction.
To reduce the effect of treatment-selection bias, matched pairs of ORC and OAH patients were created using a propensity score matching (PSM) approach.
The protein was exogenously expressed, with the expression level chosen such that the population-averaged tumble bias matched that of wild-type cells ('Materials and methods').
It has been argued that this technique may increase hidden bias because matching on observed variables may unleash bias due to hidden unobserved confounders.
