Barneveld Erik Michie Van Review

Risk sharing as a supplement to imperfect capitation in health insurance: a tt-adeoff between selection and efficiency

Risicodeling als aanvulling op imperfecte normuitkeringen voor ziektekostenverzekeringen: een afruil tussen selectie en doelmatigheid

Proefschrift tel' verkrijging van de graad van doctor aan de Erasmus Universiteit Rotterdam op gezag van de Rector Magnificus Prof.dr.P.W.C. Akkermans M.A. en volgens besluit van het College voor Promoties. De open bare verdediging zal plaatsvinden op donderdag 18 mei 2000 om 13.30 um

door

Erik Michiel van Barneveld geboren te Groot-Amillers

Pl'omotiecOIlunissie
Promotor: Overige leden: Prof.dr. W.P.M.M. van de Ven Prof.dr. E.K.A. van Doorslaer Prof.dr. W.N.J. Groot Prof.dr. E. Schokkaert Dr. R.C.J.A. van Vliet (tevensco-promotor)

Num 681 ISBN 90-9013683-5
CD

E.M,

van Barneveld, 2000

Printed by: Ridderprint, Ridderkerk

Contents
1. Introduction
1.1 1. 2 1. 3 1. 4 1.5 Regulated competition Purpose of risk sharing Research questions International relevance Other solutions 1 3 7 10 12 13

Part one: Conceptual framework

2. Selection
2.1 Tools for selection 2.2 Negative effects of selection 2.3Prevention of selection 2.4 Measuring incentives for selection 2.5 Conclusions Appendix chapter 2

19 19 21 22 31

37
41 49 49 53

3. Forms of risk sharing 3.1 Previous studies 3.2 Potential forms of risk sharing 3.3 Four forms of risk sharing 3.4 Risk sharing versus capitation 3.5 Conclusions

59
67

69 73 73
77

4. Efficiency
4. 1 Tools to improve effiCiency 4.2 Potential savings4.3 Measuring incentives for efficiency 4.4 Conclusions Appendix chapter 4

82
93

97

S. Optimizing the tradeoff 5. 1 The decision problem 5.2 Optimal proportional risk sharing variants 5.3 Conclusions Appendix chapter 5

99 99
109 122 125

Part two: Empil'ical analysis

6. Data, methods and demographic capitation payments 6.1 Data 6.2 Methods 6.3 Demographic capitation payments6.4 Conclusions Appendix chapter 6 7. rusk sharing as a snpplement to demographic capitation payments 7. 1 Proportion shared expenditures 7.2 Overall results 7.3 Selection of subgroups 7.4 Efficiency for types of care or for subgroups 7.5 Conclusions Appendix chapter 7 8. Prior costs as an additional risk adjuster 8. 1 A prior cost model versus proportional risk sharing 8.2 Overall results 8.3Prior cost models versus outlier or proportional risk sharing 8.4 Prior cost models versus risk sharing for high risks or high costs 8.5 Conclusions Appendix chapter 8

131 131 139 141 149 153 157 157 159 166 171 174 177 185 185 189 193 198 203 205

9. Conclusions and discussion 9. 1 Conclusions 9.2 Discussion

211 211 219

References Samenvatting Risicodeling aJs aanvulling op imperfectenonnuitkeringen voor ziektekostenverzekering: een aflUil tussen selectie en doelmatigheid Cnrriculum vitae Acknowledgements

227

237

255 257

1. 1111rodliClioll

1. Introduction
Market-oriented health care reforms are high on the political agenda in many countries. The main purpose of many reforms is to increase the insurers' incentives for efficiency and their responsiveness toconsumers' preferences. A common element is the introduction of capitation payments through which the insurers are (largely) financed by the regulator 1• With these payments the insurers should provide or purchase a specified set of health care services for their members during a certain period, mostly one year. In some countries the capitation payments constitute the entire revenue of insurers, but inmost countries the insurers are allowed to quote an additional premium to their members. In the latter case the regulator usually requires an insurer to quote the same additional premium to each member that chooses the same insurance modality. A common problem in all countries is the implementation of adequate capitation payments. Ideally the capitation payments should account for predictable...