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. 2019 Apr 17;188(7):1345–1354. doi: 10.1093/aje/kwz093

Figure 1.

Figure 1.

Annual numbers of published articles using propensity score matching (PSM) and coarsened exact matching (CEM) appearing in PubMed (National Library of Medicine, Bethesda, Maryland), by year, 1983–2017. Rosenbaum and Rubin’s paper introducing PSM (4) was published in 1983; since then, the body of literature based on matching has increased dramatically. Iacus et al.’s paper introducing CEM (3) was formally published in 2012, although a white paper was available earlier, and the first CEM publication in PubMed came out in 2010. The annual number of PSM publications indicates that each year, an increasing number of studies employ PSM; similarly, the annual number of studies using CEM is also starting to rise.