pairwise comparisons Mostly, arbitrary pairs of catalysts don’t even have any common elements. Can we meaningfully compare 'Na:33.2 Ti:0.5 Mn:66.3’ and 'Zn:77.8 Ce:22.2’ …? ['Na:33.2 Ti:0.5 Mn:66.3', 'Zn:77.8 Ce:22.2'] ['C:32.7 K:65.4 Pb:1.9', 'Y:100.0'] ['Na:66.7 Mo:33.3', 'Al:94.5 Mo:5.5'] ['C:4.0 Na:4.0 Ce:92.0', 'Y:70.0 Bi:30.0'] ['Si:98.2 Cs:1.8', 'Ti:50.0 Gd:50.0'] ['Na:9.1 Si:82.8 Cr:3.6 W:4.5', 'Na:20.0 Mg:80.0'] ['Y:66.7 Ba:33.3', 'Al:77.0 Ag:18.0 Ba:5.0'] ['Al:87.0 Cl:8.0 Fe:1.0 Sr:4.0', 'Na:33.2 Mn:66.3 Ta:0.5'] ['Na:1.0 La:99.0', 'Li:9.1 Ca:90.9'] ['Fe:100.0', 'Sr:50.0 Nd:50.0’] ['Al:75.0 Cl:16.0 Sr:8.0 Rh:1.0', 'Na:4.5 Si:79.2 Mn:16.3'] ['S:2.9 K:5.7 Ca:91.4', 'Sm:100.0'] ['P:34.5 Sr:65.5', 'Na:58.3 Cl:25.0 Mo:16.7'] ['Li:23.0 Si:73.2 W:3.8', 'Si:33.3 Ca:66.6 Pb:0.1'] ['Al:90.5 Ag:8.5 Pr:1.0', 'Na:66.7 Mo:33.3'] ['Cl:20.0 Ba:10.0 Nd:70.0', 'Mg:90.9 La:9.1'] ['Gd:100.0', 'Mn:50.0 Mo:50.0'] ['Na:76.9 Nb:23.1', 'La:90.0 Pb:10.0'] ['Li:6.5 S:3.2 Ca:90.3', 'P:34.5 Sr:65.5'] ['Na:5.0 Si:72.0 Cl:5.0 Mn:18.0', 'P:34.0 S:7.5 Ca:51.0 Pb:7.5']