Propensity Score Matching (PSM)
The multivariable scoring system is based on the value of the predictor variables to construct a PSM value. On the other hand, it is the probability that subject with given characteristics will receive treatment or not. To describe the propensity score, let the dichotomous (0,1) variable Z indicate treatment, and let X be the vector of available pretreatment covariates. The propensity score e(X) for an individual is defined as the conditional probability of being treated given his or her covariates X: e(X) = Pr(Z=1|X). The propensity score is a one-dimensional variable that summarizes the multidimensional pretreatment covariates X. Among persons with a given propensity score, the distribution of the covariates X is on average the same among the treated and untreated. v Method: Identify candidate predictors of the two treatments, perform a logistic regression where outcome will be two treatment, obtain a predicted probability of two treatments, this probability fo...