Fig. 2

Standardised mean difference for the paired ROC areas. The pooled ROC area for all patients with appendicitis was 0.85 (CI 0.82; 0.88) for the AIR score and 0.79 (CI 0.76; 0.81) for the Alvarado score, with a difference of 0.06 (CI 0.03; 0.09, p < 0.001). The corresponding result for advanced appendicitis was 0.96 (CI 0.94; 0.98) for the AIR score compared with 0.88 (CI 0.82; 0.95) for the Alvarado score in three reports, a difference of 0.08 (CI 0.00;0.15), p = 0.03. Gudjonsdottir [28] included only children. CI is Confidence Interval