ABSTRACT
What do we mean by composite measures? Here are two typical definitions.
The second adds a bit more to the first by referring to an underlying model and multidimensional concepts. Both of these ideas fit well with quality of care, which therefore seems particularly ripe for the use of composites. Regulators and accreditation bodies need to judge organisations from multiple angles, which means having multiple indicators of quality. Report cards and dashboards are common in many countries, which can soon get crowded with individual measures. Correlations between measures of quality are often weak, and entities as complex as healthcare providers rarely perform equally well in all aspects. As the amount of information on healthcare performance grows, so does the need to summarise it into something digestible. This has long been acknowledged in other sectors such as the hospitality industry. Summaries can be made of only a few items. For instance, TripAdvisor overall
ratings for hotels combine ratings for just six aspects such as location and service into a simple average; as we’ll see, such averaging is just one way of combining (weighting) information. The public are used to using summaries such as star ratings when choosing things like hotels and restaurants, and there are a growing number of such summaries in healthcare aimed at, and created by, the public (see Chapter 11 for more on public reporting).
