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Multilevel models for estimating incremental net benefits in multinational studies
Author(s) -
Grieve Richard,
Nixon Richard,
Thompson Simon G.,
Cairns John
Publication year - 2007
Publication title -
health economics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.55
H-Index - 109
eISSN - 1099-1050
pISSN - 1057-9230
DOI - 10.1002/hec.1198
Subject(s) - econometrics , statistics , variance (accounting) , covariate , multilevel model , multinational corporation , mathematics , economics , finance , accounting
Multilevel models (MLMs) have been recommended for estimating incremental net benefits (INBs) in multicentre cost‐effectiveness analysis (CEA). However, these models have assumed that the INBs are exchangeable and that there is a common variance across all centres. This paper examines the plausibility of these assumptions by comparing various MLMs for estimating the mean INB in a multinational CEA. The results showed that the MLMs that assumed the INBs were exchangeable and had a common variance led to incorrect inferences. The MLMs that included covariates to allow for systematic differences across the centres, and estimated different variances in each centre, made more plausible assumptions, fitted the data better and led to more appropriate inferences. We conclude that the validity of assumptions underlying MLMs used in CEA need to be critically evaluated before reliable conclusions can be drawn. Copyright © 2006 John Wiley & Sons, Ltd.