Fig. 3

SROC plots for the diagnostic accuracy of coding algorithms ascertaining acute and prevalent heart failure. Legend: a Acute heart failure (HF) algorithms and b Prevalent HF algorithms. HSROC indicates hierarchical summary receiver operating characteristic curve, grey circle, the sensitivity and (1-specificity) of an individual study with the size of the circle proportionate to study size; summary point, summary sensitivity, and specificity; 95% confidence region, 95% confidence region for the summary point, and the 95% prediction region, the area in which we can say with 95% certainty the true sensitivity and specificity of a future study will be contained