Using activity data to explore the influence of case-load size on care patterns.

BACKGROUND:A limited case-load size is considered crucial for some forms of intensive case management and many countries have undertaken extensive reorganisation of mental health services to achieve this. However, there has been limited empirical work to explore this specifically. AIMS:To test whether there is a discrete threshold for changes in intensive case management practice determined by case-load size. METHOD:"Virtual" case-load sizes were calculated for patients from their actual contacts over a 2-year period and were compared with the proportions of contacts devoted to medical and non-medical care (as a proxy for a more comprehensive service model). RESULTS:There were 39 025 recordings for 545 patients over 2 years, with a mean rate of contacts per full-time case manager per month of 48 (range 35-60). There was no variation in the proportion of non-medical contacts when case-load sizes were over 1:20 but there was a convincing linear relationship when sizes were between 1:10 and 1:20. CONCLUSIONS:Case-load size between 1:10 and 1:20 does affect the practice of case management. However, there is no support for a paradigm shift in practice at a discrete level.