Thomas R. Saving, PhD

Kilbridge correctly points out that comparative effectiveness research (CER) does not require cost data. It should also be pointed out, however, that the composition of the quality-adjusted life-year (QALY) gain of one intervention over another-whether the QALY gain is achieved mainly in the dimension of longevity or in the dimension of quality of life-has real consequences in terms of comparative costs of the interventions. Basically, a longevity increase entails additional consumption costs and additional labor earnings, essentially negative costs, during the extended life that should be included in the “cost” of an intervention.[1-3] Because labor earnings tend to be negligible relative to consumption costs toward the end of one’s life, due to sickness or retirement, failure to incorporate consumption costs and labor earnings into the comparative costs of two interventions generates a bias in favor of the intervention with the larger longevity effect.