title: Understanding and anticipating lag-time bias in cost-effectiveness studies: the role of time in cost-effectiveness analysis.
abstract: BACKGROUND
  Timely provision of information on the cost-effectiveness of innovations in health care becomes more and more important, resulting in increasing pressure on researchers to provide proof of cost-effectiveness in a short time frame. However, most of these innovations require considerable time and effort to optimally implement leading to a biased "steady state" cost-effectiveness outcome. As decision makers in health care predominantly have a short-term focus, the discrepancy between short-term study outcomes and long-term cost-effectiveness may very well lead to misguided decisions about the adoption of innovations in health care.
  
  
  METHODS
  Factors such as learning effects, capacity constraints, and delayed time to benefit are all related to a short-run timeframe and result in inefficiencies during the implementation of an innovation. These factors and the mechanisms by which they influence the cost-effectiveness outcome are explained for three different types of healthcare innovations.
  
  
  RESULTS
  As standard cost-effectiveness analysis assumes costs and effects to behave constant and representative for an innovation's entire economic lifetime, resulting cost-effectiveness outcomes might give a biased, and often overly pessimistic, reflection of the actual cost-effectiveness of an innovation. This is further amplified by the fact that short-run inefficiencies are most prevalent and impactful during an innovation's earliest stage of operation.
  
  
  CONCLUSIONS
  This study advocates to carefully take into account the different factors contributing to lag-time bias in the design and analysis of cost-effectiveness studies, and to communicate potential biases due to short-run inefficiencies to all stakeholders involved in the decision making process.
authors: Department for Health Evidence,Radboud University Medical Center,Nijmegen,The Netherlands.
authors: Gijs
authors: G
authors: van de Wetering
authors: Department of Geriatrics,Radboud University Medical Center,Nijmegen,The Netherlands.
authors: Marcel
authors: M
authors: Olde Rikkert
authors: Department for Health Evidence,Radboud University Medical Center,Nijmegen,The Netherlandseddy.adang@radboudumc.nl.
authors: Gert Jan
authors: GJ
authors: van der Wilt
authors: Department for Health Evidence,Radboud University Medical Center,Nijmegen,The Netherlandseddy.adang@radboudumc.nl.
authors: Eddy
authors: E
authors: Adang
mesh_terms: D015982:Bias; D003362:Cost-Benefit Analysis / Q000379:methods*; D006801:Humans; D007858:Learning; D013673:Technology Assessment, Biomedical / Q000191:economics* / Q000379:methods*; D013997:Time Factors
keywords: Bias