Background: In many countries, the incremental cost-effectiveness ratio (ICER) is used to assess whether an intervention is worth its costs. At the same time, policy makers often feel uncomfortable with refusing reimbursement of any intervention purely on the basis of the fact that the ICER exceeds a specific threshold value. Reluctance to define a single threshold value for the ICER seems to have been stronger in social security systems than in national healthcare services systems. This study explores how basic differences between healthcare systems impact upon the potential usefulness of an ICER threshold value.

Methods: This study is a narrative review of literature about the theoretical foundations of the ICER threshold value approach and its practical relevance in different types of healthcare systems.

Results: A single ICER threshold value cannot be maintained, defined, or measured and should not be used as a policy-making tool. None of the solutions presented up until now to make the ICER threshold approach a valuable policy-making tool overcome the important weaknesses of the approach.

Conclusions: ICERs and ICER threshold values are insufficient for assessing interventions' value for money. Rather, they should be considered as one element in the decision-making process. Complete rationalization of the decision-making process by means of quantitative decision criteria is undesirable and not feasible. Increasing transparency in the criteria used for a decision and explicitness about the relative importance of each criterion should, therefore, be the major goal.