['To determine how needs assessment is being used in Health Authorities and General Practice.', 'A postal survey of a one in two sample of Scottish GPs, semistructured interviews with selected health authority executives and a random sample of GPs.', 'Nine hundred and sixty-five GPs (54% of those sent the postal questionnaire), 47 randomly selected GP practices and 36 selected health authority (called health boards in Scotland) executives.', 'In health authorities, a view of commissioning/planning emerged with three components: (1) planning (including needs assessment); (2) leadership; and (3) strong relationships with stakeholders. Health authority executives believed that GP involvement is one of several vital components but doubted the commitment of all but a few GPs to the planning process. GPs welcomed enhanced influence but feared increases in workload and admitted to a lack of training in the skills required for needs assessment. Health authority executives aspired to place needs assessment at the centre of planning but admitted that, at present, cost and volume issues predominate. Most GPs were not involved in needs assessment and argued that it is not part of a GPs core activity. National needs assessment documents were well received by health authorities but made little or no impact on GPs.'] Does a study to determine how need assessment is being used to improve health?