A current reappraisal of Berry's hospital typology.

In an earlier article, Berry published the results of a study that examined possible relationships among hospital facilities and services. In general, Berry found that hospitals behaved in a reasonably consistent fashion; that is, hospitals added facilities and services in a well-defined order, and these facilities and services were added in distinct groups. Berry defined five such groups and hypothesized that each group represents an increasing level of case-mix complexity. Given the current interest in using Berry's results to measure hospital case mix, this study attempted to replicate Berry's results using recent data from the American Hospital Association. Using a number of statistical methodologies (including cluster analysis and Guttman scale analysis), we found that hospitals continue to add facilities and services in a well-defined order (although this order contains some notable differences from the order found by Berry). However, our results indicate that hospitals no longer add facilities and services in well-defined groups but in a more continuous fashion. Thus, it would appear that hospitals have become more differentiated.