Fig. 2.
“Jitter” diagram of PSM. Before undergoing propensity score matching (PSM) at a 1:2 ratio, unmatched treated units, and unmatched non-treated units represented the distribution of individuals in the PD and non-PD groups, respectively. After matching, the two groups were represented by matched treated units and matched non-treated units, respectively. The figure illustrates the balanced distribution of individuals in the matched groups following PSM