Table 1

Advantages and disadvantages of composite quality measures

AdvantagesDisadvantages
  • Simple, avoiding information overload in light of the growing number of performance indicators

  • Might not provide sufficient detail to enable practitioners to identify areas of need for improvement, and it can also be challenging to attribute changes in composite measures to specific quality improvement efforts

  • Able to summarise information across several quality dimensions

  • Masks potentially important variations in quality, for example, if performance on morbidity and mortality does not correlate with other dimensions such as the patient experience

  • Improved rankability compared with the use of a single indicator, even if that indicator is produced using data that span multiple years

  • The weights attached to the individual indicators might not reflect their importance to the users of the data, particularly if users place different values on different aspects of care quality

  • Helps overcome problems associated with small sample sizes for individual quality indicators (eg, a small to medium hospital may have few deaths, but many readmissions), analogous to their appeal in clinical trials20

  • The constituent indicators might have varying levels of robustness (eg, with regard to gaming or coding practices), making it hard to assess the validity of the composite measure

  • It can be challenging to adjust composite measures for differences in patient characteristics between providers, when the relevant predictors can differ between one constituent indicator to the next