The validity of using health state indexes in measuring the consequences of traffic injury for public health

This paper describes an assessment of the validity of using health state indexes as a means of describing the consequences of traffic injury for public health. Three issues are discussed: (1) Can questionnaire data be used as input for estimating health state values by means of health state indexes? (2) Can the validity of describing the consequences of traffic injury by means of different health state indexes (QALY-indexes) be assessed? (3) Can estimated health state values be used directly as a basis for decision making? It is concluded that questionnaire data can be used as input for health state value estimation. Four health state indexes are compared: The Quality of Well Being Scale, The McMaster Health Classification System, The Rosser and Kind Index and The EuroQol Instrument (transformed version). It is concluded that an assessment of the validity of these indexes is possible, and that the EuroQol Instrument appears to be the most valid of the four indexes that are compared. None of the four indexes give values that are consistent with public policy objectives, but objectives were not set with the benefit of knowing the relative utility loss associated with injuries at different levels of severity.