This paper examines the use of development centre methodology to measure the gap in performance for fieldwork staff in a social welfare organisation. The process follows the construction of a capability framework, a set of work-based simulations for participants and the use of a 360-degree instrument. These processes are combined to measure and compare capabilities of both high level performers and a random selection of staff at various levels within the organisation. The results are analysed in the context of a range of organisation development options. (Contains 1 table and 1 figure.)