Is there a time trend in medical practice variations?: a review of the literature and an critical analysis of theoretical approaches.

The aim of this study was to review the research evidence for a decreasing time trend in medical practice variation and to contribute to our theoretical understanding of trends in medical practice variations. We searched Pubmed for articles reporting on time trends in medical practice variations. Eleven relevant articles were identified. The studies we found tend to show a downward trend in practice variation. Six of the eleven studies show a decrease in practice variation, three studies report more or less stable variation, and only two show increasing variation. The number of the studies is, however, small and the aspects of medical practice that were studied in these articles are diverse. A trend in medical practice variation can probably best be explaned by institutional changes within and outside healthcare, which on the one hand directly lead to decreased practice variation and on the other hand make the working environment of physicians more uniform.