This paper evaluates the use of a support network measurement instrument (PANT) in social work practice, focusing primarily on a study of the introduction and use of the instrument with social work teams. The paper describes practitioners' responses during the training period and during the initial phases of using the instrument in practice. The findings show how growth in familiarity with the new tool and support from managers overcame early resistance and contributed to both practitioners' confidence and understanding of the situations of older people. It allowed them to tailor interventions appropriately. It also contributed to understanding of differences between teams in the area and made it possible to create area profiles of older service users, their carers and their needs. The importance of network type for prediction of outcomes is stressed.