“…In the preceding section we argued that the modal research design in our collection of seminal papers in the field is an empirical study that tests theoretical implications with correlational evidence from observational studies, which is also the case in more recent research. Of all publications in the journals we reviewed, 95 explore electoral systems in some form: 88 are quantitative studies and explicitly empirically operationalize electoral systems as either an independent variable (79), as a dependent variable (Aytaç, 2014;Cantú, 2014;Curtice and Marsh, 2014), as both independent and dependent variables (Endersby and Towle, 2014;Miller, 2014), or do not explicitly operationalize electoral institutions but make comparisons across institutions (Adams, Ezrow and Somer-Topcu, 2014;Clark and Leiter, 2014;Grossman and Woll, 2014;Spoon and Klüver, 2014); 5 Two studies are formal theoretical (Cho, 2014;Gans-Morse, Mazzuca and Nichter, 2014) and one is normative (Murray, 2014); and, four studies discuss measurement issues (Krook, 2014;Otjes and Louwerse, 2014;Wawro and Katznelson, 2014;Wilson, 2014).…”