In recent years, quality of care has occupied a prominent place in health care. Different performance indicators are used to assess the quality of care. There is some debate about the value of outcome versus process indicators in measuring aspects of quality of care. Van de Geer et al. carried out a field study in a medical rehabilitation centre in the Netherlands in which four low task uncertainty teams ('hand trauma', 'heart failure', 'amputation', 'chronic pain'), and four high task uncertainty teams ('children with developmental coordination disorder', 'Parkinson disease', 'young children (aged 1-4 years) with developmental disorders', 'acquired brain injuries') participated in the development of performance indicators. They concluded that task uncertainty is an important factor to be considered in the development of indicators, and in the choice between the use of process and outcome indicators. Notably, outcome indicators are only useful in health problems with little variation and little task uncertainty, while many tasks are complex and uncertain. The participation of health care professionals in the development of quality indicators is, therefore, very important.