Construct Design Matrices for OPSR Model Fits
# S3 method for opsr
model.matrix(object, data, .filter = NULL, ...)A list of lists with the design matrices W (selection process) and
X (outcome process). Both of these lists have object$nReg elements (a
separate design matrix for each regime).
an object of class "opsr".
a data frame containing the terms from object$formula. Passed to
model.frame.opsr. Can be omitted.
used internally in predict.opsr for counterfactual predictions.
further arguments passed to or from other methods.
model.frame.opsr, stats::model.matrix