Heatmaps and confusion matrix for the study group ‘Berlin’. Data were obtained using the study group ‘Berlin’ (10 control group (CG), 10 osteoarthritis (OA), 10 rheumatoid arthritis (RA)) as the training set for the rule generation and re-applying the respective rules to the same dataset. (A) Heatmap of the membership weights applying all rules of the primary rule set (α = 0.94; ‘CG’, 221 rules; ‘OA’, four rules; ‘RA’, 29 rules) for the prediction of the clinical status of the different samples; dashed red lines indicate the lower limits of the respective pruned lists of rules subsequently applied in (B). (B) Heatmap of the membership weights applying pruned lists of rules (α = 0.94; ‘CG’, eight top-ranked rules; ‘OA’, four top-ranked rules; ‘RA’, eight top-ranked rules) for optimized prediction of the clinical status of the different samples. (C) Confusion matrix for the rule set displayed in heatmap (B). TP, true positives; TN, true negatives; FP, false positives; FN, false negatives.