What is the value of hospital mortality indicators, and are there ways to do better?

Monitoring hospital performance using patient safety indicators is one of the key components of healthcare reform in Australia. Mortality indicators, including the hospital standardised mortality ratio and deaths in low mortality diagnosis reference groups have been included in the core national hospital-based outcome indicator set recommended for local generation and review and public reporting. Although the face validity of mortality indicators such as these is high, an increasing number of studies have demonstrated that there are concerns regarding their internal, construct and criterion validity. Use of indicators with poor validity has the consequence of potentially incorrectly classifying hospitals as performance outliers and expenditure of limited hospital staff time on activities which may provide no gain to hospital quality and safety and may in fact cause damage to morale. This paper reviews the limitations of current approaches to monitoring hospital quality and safety performance using mortality indicators. It is argued that there are better approaches to improving performance than monitoring with mortality indicators generated from hospital administrative data. These approaches include use of epidemiologically sound, clinically relevant data from clinical-quality registries, better systems of audit, evidence-based bundles, checklists, simulators and application of the science of complex systems.