The quality of the included evidence ranged from high to very low. Evidence was downgraded for a number of reasons including indirectness of the population (as they were recruited previous to 2001 when the guidelines for CHF management were changed), risk of bias for reasons including a lack of calibration data, or inconsistency due to variability in discrimination statistics reported by the studies with a concomitant lack of overlap in the confidence intervals. A single high quality study (n=10,930) reported both the sensitivity and specificity of the SHFM at 50% and 20% mortality thresholds. At a mortality threshold of 50% the SHFM showed a very poor sensitivity of 0.05 and a good specificity of 0.99 and at the 20% threshold it showed a very poor sensitivity of 0.21 and a good specificity of 0.93. The same study reported the prognostic accuracy of the MAGGIC project heart failure risk score at these thresholds. It reported a very poor sensitivity of 0.3 and a good specificity of 0.99 at the 50% mortality threshold and a moderate sensitivity of 0.7 and moderate specificity of 0.61 at the 20% mortality threshold. Seven further studies ranging from moderate to low quality, reported AUC or c-statistics for the SHFM. The largest of the studies (n=10,930) reported a moderate c-statistic of 0.66. The remaining studies were considerably smaller (ranging in sample size from 872 to 5010) and were mostly rated as low quality. The discrimination statistics reported by these studies ranged from 0.66 to 0.76 with only a proportion of them reporting confidence intervals. Moderate quality evidence was found for a single study (n=676) reporting on an untitled risk tool which combined data from the 6MWT and NT-proBNP. This tool reported a moderate c-statistic of 0.68. 