The Derriford Appearance Scale (DAS59): a new psychometric scale for the evaluation of patients with disfigurements and aesthetic problems of appearance.

The DAS59 has been designed and developed to meet the need for an objective measure of the spectrum of psychological distress and dysfunction that is characteristic of disfigurements, deformities and aesthetic problems of appearance. Content validity has been assured by basing the scale's items on a detailed autobiographical study of representative patients. Internal consistency is high (0.98) and test-retest reliabilities are good (general population: 0.75; clinical population: 0.86). Correlations with other appropriate standardised tests show good criterion validity and good construct validity. Factor analysis of 2741 data sets (general population and clinical population) identified three factors that are not feature specific and two that are (bodily and sexual features, facial features). The DAS59 thus generates a full-scale score and five factorial sub-scale scores. The DAS59 has been standardised on the clinical population across a range of patient groups and on the general population subdivided into those concerned and those not concerned about appearance. The DAS59 is highly sensitive as a measure of change following treatment with large and significant preoperative-postoperative reductions in full-scale and factorial scores of patients treated for facial features or bodily/sexual features. The DAS59 offers benefits for patient selection in both cosmetic and reconstructive plastic surgery and in the evaluation of outcome. It provides valid and reliable data for clinical audit and governance and for evaluating the merits of one treatment protocol against another.