THE LEAD TIME TRADE-OFF: THE CASE OF HEALTH STATES BETTER THAN DEATH

The Lead Time Trade-Off (L-TTO) is a variant of the TTO method that tries to overcome some of the problems of the most widely used method (Torrance, 1986) for health states worse than death (SWD). Theoretically, the new method reduces the problems that have been detected when researchers have elicited preferences for SWD. However, several questions remain to be clarified. One of them is the influence of this new method for states better than death (SBD). In this paper we try to shed some light on this issue using a split sample design (n=500). One subsample (n=188) was interviewed using L-TTO and the rest using the traditional TTO (T-TTO). Our results show that the L-TTO produces utilities that are consistently higher than the T-TTO for SBD. Furthermore, the higher the severity the higher the difference between both methods. Another finding is that the L-TTO seems to produce a lower number of SWD. This effect seems to be concentrated in the most severe health states. This implies a violation of additive separability, one of the cornerstones of the QALY model. Our data show that the L-TTO may be different from the T-TTO in more respects than those that were originally intended.Lead Time Trade-Off, QALYs, Discounting, Additive Independece