title: Economics in "Global Health 2035": a sensitivity analysis of the value of a life year estimates.
abstract: BACKGROUND
  In "Global health 2035: a world converging within a generation,"The LancetCommission on Investing in Health (CIH) adds the value of increased life expectancy to the value of growth in gross domestic product (GDP) when assessing national well-being. To value changes in life expectancy, the CIH relies on several strong assumptions to bridge gaps in the empirical research. It finds that the value of a life year (VLY) averages 2.3 times GDP per capita for low- and middle-income countries (LMICs) assuming the changes in life expectancy they experienced from 2000 to 2011 are permanent.
  
  
  METHODS
  The CIH VLY estimate is based on a specific shift in population life expectancy and includes a 50 percent reduction for children ages 0 through 4. We investigate the sensitivity of this estimate to the underlying assumptions, including the effects of income, age, and life expectancy, and the sequencing of the calculations.
  
  
  RESULTS
  We find that reasonable alternative assumptions regarding the effects of income, age, and life expectancy may reduce the VLY estimates to 0.2 to 2.1 times GDP per capita for LMICs. Removing the reduction for young children increases the VLY, while reversing the sequencing of the calculations reduces the VLY.
  
  
  CONCLUSIONS
  Because the VLY is sensitive to the underlying assumptions, analysts interested in applying this approach elsewhere must tailor the estimates to the impacts of the intervention and the characteristics of the affected population. Analysts should test the sensitivity of their conclusions to reasonable alternative assumptions. More work is needed to investigate options for improving the approach.
authors.affiliation: Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
authors.forename: Angela Y
authors.initials: AY
authors.lastname: Chang
authors.affiliation: Center for Health Decision Science, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Center for Risk Analysis, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Robinson
authors.affiliation: Center for Health Decision Science, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Center for Risk Analysis, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Toulouse School of Economics, University of Toulouse Capitole, Toulouse, France.
authors.forename: James K
authors.initials: JK
authors.lastname: Hammitt
authors.affiliation: Center for Health Decision Science, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Resch
mesh_terms: D002675:Child, Preschool; D003906:Developing Countries; D004467:Economics; D014943:Global Health / Q000592:standards*; D059066:Gross Domestic Product / Q000639:trends*; D006801:Humans; D007182:Income / Q000706:statistics & numerical data*; D007223:Infant; D007231:Infant, Newborn; D008017:Life Expectancy / Q000639:trends*; D026712:Value of Life / Q000191:economics*