Value of information analysis (VOI)

When used in health technology assessment, value of information (VOI) analysis is an umbrella term referring to the estimation of the value, in terms of cost and health outcomes, of collecting more data/information on key parameters that influence a decision, such as reimbursement of a new technology. Typically, this is most useful where the output of an economic evaluation (e.g. incremental cost-effectiveness ratio) is uncertain yet close to a decision threshold (willingness to pay), and a key parameter on which the output is based is itself uncertain. As such, new information reducing uncertainty in that parameter will increase the chance of the correct decision being made, and the ‘value’ of this information is a function of how likely it would enable a decision to be made or changed. The usefulness of collecting information on parameters that have high certainty, or those which have a small bearing on the output of the economic evaluation, is likely to be low. VOI analysis may be particularly useful in assessing whether a further, expensive, study is likely to yield helpful results (e.g. of effectiveness). VOI analysis may be performed using conventional economic models as long as they include probabilistic sensitivity analysis. Common outputs of VOI analysis are the expected value of perfect information, expected value of partially perfect information and expected value of sample information.