Summary. A well-known result in the medical insurance literature is that zero co-insurance is never second-best for insurance contracts
subject to moral hazard. We replace the usual expected utility assumption with a version of the rank-dependent utility (RDU)
model that has greater experimental support. When consumers exhibit such preferences, we show that zero co-insurance may in
fact be optimal, especially for low-risk consumers. Indeed, it is even possible that the first-best and second-best contracts
are identical. In this case, there is no “market failure”, despite the informational asymmetry. We argue that these RDU results are in
better accord with the empirical evidence from US health insurance markets.
Received: February 26, 2001; revised version: October 4, 2002
RID="*"
ID="*"The authors would particularly like to thank Simon Grant, John Quiggin, Peter Wakker and an anonymous referee for valuable
comments and suggestions on earlier drafts. The paper has also benefitted from the input of seminar audiences at The Australian
National University, University of Auckland, University of Melbourne and University of Sydney. Ryan also gratefully acknowledges
the financial support of the ARC, through Grant number A000000055.
Correspondence to:R. Vaithianathan 相似文献
Background: Validation of overall survival (OS) extrapolations of immune-checkpoint inhibitors (ICIs) during the National Institute for Health and Care Excellence (NICE) Single Technology Assessment (STA) process is limited due to data still maturing at the time of submission. Inaccurate extrapolation may lead to inappropriate decision-making. The availability of more mature trial data facilitates a retrospective analysis of the plausibility and validity of initial extrapolations. This study compares these extrapolations to subsequently available longer-term data.
Methods: A systematic search of completed NICE appraisals of ICIs from March 2000 to December 2017 was performed. A targeted search was also undertaken to procure published OS data from the pivotal clinical trials for each identified STA made available post-submission to NICE. Initial Kaplan-Meier curves and associated extrapolations from NICE documentation were extracted to compare the accuracy of OS projections versus the most mature data.
Results: The review identified 11 STAs, of which 10 provided OS data upon submission to NICE. The extrapolations undertaken considered parametric or piecewise survival models. Additional data cut-offs provided a mean of 18 months of OS beyond the end of the original data. Initial extrapolations typically under-estimated OS from the most mature data cut-off by 0.4–2.7%, depending on the choice of assessment method and use of the manufacturer- or ERG-preferred extrapolation.
Conclusion: Long-term extrapolation of OS is required for NICE STAs based on initial immature OS data. The results of this study demonstrate that the initial OS extrapolations employed by manufacturers and ERGs generally predicted OS reasonably well when compared to more mature data (when available), although on average they appeared to underestimate OS. This review and validation shows that, while the choice of OS extrapolation is uncertain, the methods adopted are generally aligned with later-published follow-up data and appear appropriate for informing HTA decisions. 相似文献