On the societal value of health care: what do we know about the person trade-off technique?

The person trade-off (PTO) technique has been suggested as a means of eliciting social preferences for health care, both the valuation of health care interventions and, more recently, to inform on the weights that society may attach to other decision-making criteria (e.g. the severity of a patients pre-treatment condition). Given the increased attention afforded to the PTO technique, this review examines the current evidence to inform on the ability of the PTO to provide a measure of social preference. Applying criteria of practicality, reliability and validity to empirical and theoretical contributions to the PTO literature, the review finds that the technique has limited empirical support. Applications of the PTO have been in a largely experimental setting, the reliability of the PTO is unproven and the empirical validity of the technique, in terms its ability to reflect actual preferences, remains unclear. In the broader context of the valuation of health states or outcomes, all techniques are open to criticism. Given this position, the review finds support for the potential of the PTO in the assessment of the societal value of health care, and it supports further empirical inquiry on the PTO.