Abstract
Decision aids, sometimes known as decision-support tools, are increasingly used to help patients to understand treatment options and to reach an informed decision consistent with their own values, yet methods for their economic evaluation have received limited attention. This is at odds with the increasingly rigorous methods being applied to assess the cost effectiveness of other health technologies. This paper reviews current approaches to evaluating decision aids and proposes a new method for assessing their benefits relative to other interventions in a resource-constrained health system that seeks to improve health, equity and patient satisfaction. Current evaluation frameworks are found to be unsuitable for the economic evaluation of decision aids since their objectives are broader than health maximisation. Decision aids may generate significant non-health benefits such as improved patient knowledge and satisfaction, which cannot be assessed using cost-utility analysis. A stated-preference consultation time trade-off (CTTO) is proposed in which a proportion of hypothetical physician consultation is traded for use of the decision aid. A decision aid provides information for a patient to make an informed choice and therefore may be considered to be a substitute for physician time. The CTTO can be reported in consultation minutes or converted to monetary units using the cost of physician time. These values may be used, alongside the implementation cost, for economic evaluation.