Summary function to compare SMD of the key covariates in matched and the full set of treated units.
check_representative(matching_result, match_num = NULL)a summary table of SMDs of the key covariates between the whole treated units and the matched treated units.
the matching result returned by either dist_bal_match or two_dist_match.
(optional) Integer index of match that the user want to extract paired observations from. NULL by default, which will generate a table for all the matches.