This article summarises experience of evaluation gained over 9 years of providing cognitive-behavioural rehabilitation . Measures of impairment are not particularly useful as indicators of outcome but do contribute to rehabilitatio n planning. Measurement of disability is central to rehabilitatio n but current measures have a limited ability to assess cognitive disability despite their relative strength in assessing physical problems. Goal setting is an integral part of the rehabilitatio n process but has limited utility in the evaluation of outcome. Although handicap is important as an index of outcome, this is difficult to measure whilst the person is resident in a rehabilitation centre. The use of modified measures and methods of assessment have helped to compensate for some of the limitations . However, new or revised measures are needed to allow repeated measurement and to enable satisfactory assessment of change in cognitive disabilities.There are several aspects of a service that influence the selection of methods for assessment. These include historical factors, the design and aims of the programme, the constitution of the rehabilitation team, and of course, the nature of the patients' difficulties and goals.Our Brain Injury Rehabilitation Service was initially set up at Ticehurst in 1989 as an inpatient and day patient unit for those with cognitive and Requests for reprints should be sent to Michael Oddy, Ticehurst House Hospital, Ticehurst, Wadhurst, East Sussex TN5 7HU, UK.