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SeaTE: Subjective ex ante Treatment Effect of Health on Retirement

Author

Listed:
  • Pamela Giustinelli

    (Bocconi University, IGIER, and LEAP)

  • Matthew D. Shapiro

    (University of Michigan and NBER)

Abstract
This paper develops an innovative approach to measuring the effect of health on retirement. The approach elicits subjective probabilities of working at specified time horizons fixing health level. Using a treatment-effect framework, within-individual differences in elicited probabilities of working given health yield individual-level estimates of the causal effect of health (the treatment) on working (the outcome). We call this effect the Subjective ex ante Treatment Effect (SeaTE). The paper then develops a dynamic programming framework for the SeaTE. This framework allows measurement of individual-level value functions that map directly into the dynamic programming model commonly used in structural microeconometric analysis of retirement. The paper analyzes conditional probabilities elicited in the Vanguard Research Initiative (VRI)—a survey of older Americans with positive assets. Among workers 58 and older, a shift from high to low health would on average reduce the odds of working by 28.5 percentage points at a two-year horizon and 25.7 percentage points at a four-year horizon. There is substantial variability across individuals around these average SeaTEs, so there is substantial heterogeneity in taste for work or returns to work. This heterogeneity would be normally unobservable and hard to disentangle from other determinants of retirement in data on realized labor supply decisions and health states. The paper’s approach can overcome the problem that estimates of the effect of health on labor supply based on behavioral (realizations) data can easily overstate the effect of health on retirement whenever less healthy workers tend to retire earlier for reasons other than health.

Suggested Citation

  • Pamela Giustinelli & Matthew D. Shapiro, 2018. "SeaTE: Subjective ex ante Treatment Effect of Health on Retirement," Working Papers wp382, University of Michigan, Michigan Retirement Research Center.
  • Handle: RePEc:mrr:papers:wp382
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    1. Gong, Yifan & Stinebrickner, Ralph & Stinebrickner, Todd, 2022. "Marriage, children, and labor supply: Beliefs and outcomes," Journal of Econometrics, Elsevier, vol. 231(1), pages 148-164.
    2. John Ameriks & Joseph Briggs & Andrew Caplin & Minjoon Lee & Matthew D. Shapiro & Christopher Tonetti, 2020. "Older Americans Would Work Longer If Jobs Were Flexible," American Economic Journal: Macroeconomics, American Economic Association, vol. 12(1), pages 174-209, January.
    3. Arthur Van Soest & Arie Kapteyn & Julie Zissimopoulos, 2006. "Using Stated Preferences Data to Analyze Preferences for Full and Partial Retirement," Working Papers WR-345, RAND Corporation.
    4. Thierry Magnac & David Thesmar, 2002. "Identifying Dynamic Discrete Decision Processes," Econometrica, Econometric Society, vol. 70(2), pages 801-816, March.
    5. Cai, Lixin, 2010. "The relationship between health and labour force participation: Evidence from a panel data simultaneous equation model," Labour Economics, Elsevier, vol. 17(1), pages 77-90, January.
    6. Cornelissen, Thomas & Dustmann, Christian & Raute, Anna & Schönberg, Uta, 2016. "From LATE to MTE: Alternative methods for the evaluation of policy interventions," Labour Economics, Elsevier, vol. 41(C), pages 47-60.
    7. V. Joseph Hotz & Robert A. Miller, 1993. "Conditional Choice Probabilities and the Estimation of Dynamic Models," The Review of Economic Studies, Review of Economic Studies Ltd, vol. 60(3), pages 497-529.
    8. Aguirregabiria, Victor & Mira, Pedro, 2010. "Dynamic discrete choice structural models: A survey," Journal of Econometrics, Elsevier, vol. 156(1), pages 38-67, May.
    9. Orazio P. Attanasio, 2009. "Expectations and Perceptions in Developing Countries: Their Measurement and Their Use," American Economic Review, American Economic Association, vol. 99(2), pages 87-92, May.
    10. James J. Heckman & Jeffrey A. Smith, 1995. "Assessing the Case for Social Experiments," Journal of Economic Perspectives, American Economic Association, vol. 9(2), pages 85-110, Spring.
    11. John Rust & Christopher Phelan, 1997. "How Social Security and Medicare Affect Retirement Behavior in a World of Incomplete Markets," Econometrica, Econometric Society, vol. 65(4), pages 781-832, July.
    12. Stefan Wager & Susan Athey, 2018. "Estimation and Inference of Heterogeneous Treatment Effects using Random Forests," Journal of the American Statistical Association, Taylor & Francis Journals, vol. 113(523), pages 1228-1242, July.
    13. Gustman, Alan L. & Steinmeier, Thomas L. & Tabatabai, Nahid, 2010. "Pensions in the Health and Retirement Study," Economics Books, Harvard University Press, number 9780674048669, Spring.
    14. Courtney Coile & Kevin Milligan & David A. Wise, 2017. "Health Capacity to Work at Older Ages: Evidence from the United States," NBER Chapters, in: Social Security Programs and Retirement around the World: The Capacity to Work at Older Ages, pages 359-394, National Bureau of Economic Research, Inc.
    15. Michael C. Knaus & Michael Lechner & Anthony Strittmatter, 2022. "Heterogeneous Employment Effects of Job Search Programs: A Machine Learning Approach," Journal of Human Resources, University of Wisconsin Press, vol. 57(2), pages 597-636.
    16. John Ameriks & Andrew Caplin & Minjoon Lee & Matthew D. Shapiro & Christopher Tonetti, 2015. "The Wealth of Wealthholders," NBER Working Papers 20972, National Bureau of Economic Research, Inc.
    17. Eric French, 2005. "The Effects of Health, Wealth, and Wages on Labour Supply and Retirement Behaviour," The Review of Economic Studies, Review of Economic Studies Ltd, vol. 72(2), pages 395-427.
    18. Pamela Giustinelli & Charles F. Manski, 2018. "Survey Measures Of Family Decision Processes For Econometric Analysis Of Schooling Decisions," Economic Inquiry, Western Economic Association International, vol. 56(1), pages 81-99, January.
    19. Jürgen Maurer & Roger Klein & Francis Vella, 2011. "Subjective Health Assessments and Active Labor Market Participation of Older Men: Evidence from a Semiparametric Binary Choice Model with Nonadditive Correlated Individual-specific Effects," The Review of Economics and Statistics, MIT Press, vol. 93(3), pages 764-774, August.
    20. Charles F. Manski, 2018. "Survey Measurement of Probabilistic Macroeconomic Expectations: Progress and Promise," NBER Macroeconomics Annual, University of Chicago Press, vol. 32(1), pages 411-471.
    21. Hudomiet, Péter & Hurd, Michael D. & Parker, Andrew M. & Rohwedder, Susann, 2021. "The effects of job characteristics on retirement," Journal of Pension Economics and Finance, Cambridge University Press, vol. 20(3), pages 357-373, July.
    22. Arrondel, Luc & Calvo-Pardo, Hector & Giannitsarou, Chryssi & Haliassos, Michael, 2022. "Informative social interactions," Journal of Economic Behavior & Organization, Elsevier, vol. 203(C), pages 246-263.
    23. Péter Hudomiet & Robert J. Willis, 2013. "Estimating Second Order Probability Beliefs from Subjective Survival Data," Decision Analysis, INFORMS, vol. 10(2), pages 152-170, June.
    24. Disney, Richard & Emmerson, Carl & Wakefield, Matthew, 2006. "Ill health and retirement in Britain: A panel data-based analysis," Journal of Health Economics, Elsevier, vol. 25(4), pages 621-649, July.
    25. F. Thomas Juster, 1966. "Consumer Buying Intentions and Purchase Probability: An Experiment in Survey Design," NBER Books, National Bureau of Economic Research, Inc, number just66-2.
    26. van der Klaauw, Wilbert & Wolpin, Kenneth I., 2008. "Social security and the retirement and savings behavior of low-income households," Journal of Econometrics, Elsevier, vol. 145(1-2), pages 21-42, July.
    27. Richard Blundell & Jack Britton & Monica Costa Dias & Eric French, 2016. "The Dynamic Effects of Health on the Employment of Older Workers," Working Papers wp348, University of Michigan, Michigan Retirement Research Center.
    28. James J. Heckman, 2010. "Building Bridges between Structural and Program Evaluation Approaches to Evaluating Policy," Journal of Economic Literature, American Economic Association, vol. 48(2), pages 356-398, June.
    29. Peter Arcidiacono & Paul B. Ellickson, 2011. "Practical Methods for Estimation of Dynamic Discrete Choice Models," Annual Review of Economics, Annual Reviews, vol. 3(1), pages 363-394, September.
    30. Kathleen McGarry, 2004. "Health and Retirement: Do Changes in Health Affect Retirement Expectations?," Journal of Human Resources, University of Wisconsin Press, vol. 39(3).
    31. Asher A. Blass & Saul Lach & Charles F. Manski, 2010. "Using Elicited Choice Probabilities To Estimate Random Utility Models: Preferences For Electricity Reliability," International Economic Review, Department of Economics, University of Pennsylvania and Osaka University Institute of Social and Economic Research Association, vol. 51(2), pages 421-440, May.
    32. Arthur Van Soest & Hana Vonkova, 2014. "How Sensitive Are Retirement Decisions To Financial Incentives? A Stated Preference Analysis," Journal of Applied Econometrics, John Wiley & Sons, Ltd., vol. 29(2), pages 246-264, March.
    33. Michael D. Hurd, 2009. "Subjective Probabilities in Household Surveys," Annual Review of Economics, Annual Reviews, vol. 1(1), pages 543-564, May.
    34. A. D. Roy, 1951. "Some Thoughts On The Distribution Of Earnings," Oxford Economic Papers, Oxford University Press, vol. 3(2), pages 135-146.
    35. Pamela Giustinelli & Charles F. Manski & Francesca Molinari, 2019. "Precise or Imprecise Probabilities? Evidence from Survey Response on Late-onset Dementia," NBER Working Papers 26125, National Bureau of Economic Research, Inc.
    36. Kalouptsidi, Myrto & Souza-Rodrigues, Eduardo & Scott, Paul, 2017. "Identification of Counterfactuals in Dynamic Discrete Choice Models," CEPR Discussion Papers 12470, C.E.P.R. Discussion Papers.
    37. Myrto Kalouptsidi & Paul T. Scott & Eduardo Souza-Rodrigues, 2015. "Identification of Counterfactuals in Dynamic Discrete Choice Models," NBER Working Papers 21527, National Bureau of Economic Research, Inc.
    38. Kerry McGeary, 2009. "How do health shocks influence retirement decisions?," Review of Economics of the Household, Springer, vol. 7(3), pages 307-321, September.
    39. Michael Haliassos & Hector F. CALVO PARDO & Chryssi Giannitsarou & Luc Arrondel, 2016. "Informative Social Interactions," 2016 Meeting Papers 636, Society for Economic Dynamics.
    40. Wilbert van der Klaauw, 2012. "On the Use of Expectations Data in Estimating Structural Dynamic Choice Models," Journal of Labor Economics, University of Chicago Press, vol. 30(3), pages 521-554.
    41. Adeline Delavande, 2014. "Probabilistic Expectations in Developing Countries," Annual Review of Economics, Annual Reviews, vol. 6(1), pages 1-20, August.
    42. Grossman, Michael, 1972. "On the Concept of Health Capital and the Demand for Health," Journal of Political Economy, University of Chicago Press, vol. 80(2), pages 223-255, March-Apr.
    43. Gustman, Alan L. & Steinmeier, Thomas L., 2005. "The social security early entitlement age in a structural model of retirement and wealth," Journal of Public Economics, Elsevier, vol. 89(2-3), pages 441-463, February.
    44. Anna, Petrenko, 2016. "Мaркування готової продукції як складова частина інформаційного забезпечення маркетингової діяльності підприємств овочепродуктового підкомплексу," Agricultural and Resource Economics: International Scientific E-Journal, Agricultural and Resource Economics: International Scientific E-Journal, vol. 2(1), March.
    45. Pilar Garcia-Gomez & Titus J. Galama & Eddy van Doorslaer & Angel Lopez-Nicolas, 2017. "Interactions Between Financial Incentives and Health in the Early Retirement Decision," Tinbergen Institute Discussion Papers 17-044/V, Tinbergen Institute.
    46. Zvi Eckstein & Kenneth I. Wolpin, 1989. "The Specification and Estimation of Dynamic Stochastic Discrete Choice Models: A Survey," Journal of Human Resources, University of Wisconsin Press, vol. 24(4), pages 562-598.
    47. Dwyer, Debra Sabatini & Mitchell, Olivia S., 1999. "Health problems as determinants of retirement: Are self-rated measures endogenous?," Journal of Health Economics, Elsevier, vol. 18(2), pages 173-193, April.
    48. Yu Zheng & Juan Pantano, 2012. "Using Subjective Expectations Data to Allow for Unobserved Heterogeneity in Hotz-Miller Estimation Strategies," 2012 Meeting Papers 940, Society for Economic Dynamics.
    49. Jonathan M.V. Davis & Sara B. Heller, 2017. "Using Causal Forests to Predict Treatment Heterogeneity: An Application to Summer Jobs," American Economic Review, American Economic Association, vol. 107(5), pages 546-550, May.
    50. Susan Athey & Guido Imbens & Thai Pham & Stefan Wager, 2017. "Estimating Average Treatment Effects: Supplementary Analyses and Remaining Challenges," American Economic Review, American Economic Association, vol. 107(5), pages 278-281, May.
    51. Matthew Wiswall & Basit Zafar, 2016. "Human Capital Investments and Expectations about Career and Family," NBER Working Papers 22543, National Bureau of Economic Research, Inc.
    52. Courtney C. Coile, 2015. "Economic Determinants Of Workers’ Retirement Decisions," Journal of Economic Surveys, Wiley Blackwell, vol. 29(4), pages 830-853, September.
    53. Sudipto Banerjee & David Blau, 2016. "Employment Trends by Age in the United States: Why Are Older Workers Different?," Journal of Human Resources, University of Wisconsin Press, vol. 51(1), pages 163-199.
    54. Maarten Lindeboom & Marcel Kerkhofs, 2009. "Health and work of the elderly: subjective health measures, reporting errors and endogeneity in the relationship between health and work," Journal of Applied Econometrics, John Wiley & Sons, Ltd., vol. 24(6), pages 1024-1046.
    55. John Bound, 1991. "Self-Reported Versus Objective Measures of Health in Retirement Models," Journal of Human Resources, University of Wisconsin Press, vol. 26(1), pages 106-138.
    56. Wändi Bruine de Bruin & Paul S. Fischbeck & Neil A. Stiber & Baruch Fischhoff, 2002. "What Number is “Fifty‐Fifty”?: Redistributing Excessive 50% Responses in Elicited Probabilities," Risk Analysis, John Wiley & Sons, vol. 22(4), pages 713-723, August.
    57. Kevin Milligan & Tammy Schirle, 2017. "Health Capacity to Work at Older Ages: Evidence from Canada," NBER Chapters, in: Social Security Programs and Retirement around the World: The Capacity to Work at Older Ages, pages 59-83, National Bureau of Economic Research, Inc.
    58. Heckman, James J, 1996. "Randomization as an Instrumental Variable: Notes," The Review of Economics and Statistics, MIT Press, vol. 78(2), pages 336-341, May.
    59. Anne Case & Angua Deaton, 2015. "Rising morbidity and mortality in midlife among white non-Hispanic Americans in the 21st century," Working Papers 15078.full.pdf, Princeton University, Woodrow Wilson School of Public and International Affairs, Research Program in Development Studies..
    60. Courtney Coile & Kevin S. Milligan & David A. Wise, 2016. "Health Capacity to Work at Older Ages: Evidence from the U.S," NBER Working Papers 21940, National Bureau of Economic Research, Inc.
    61. Peter Arcidiacono & V. Joseph Hotz & Arnaud Maurel & Teresa Romano, 2020. "Ex Ante Returns and Occupational Choice," Journal of Political Economy, University of Chicago Press, vol. 128(12), pages 4475-4522.
    62. Arie Kapteyn & Erik Meijer, 2014. "A Comparison of Different Measures of Health and their Relation to Labor Force Transitions at Older Ages," NBER Chapters, in: Discoveries in the Economics of Aging, pages 115-150, National Bureau of Economic Research, Inc.
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    Cited by:

    1. Gong, Yifan & Stinebrickner, Ralph & Stinebrickner, Todd, 2022. "Marriage, children, and labor supply: Beliefs and outcomes," Journal of Econometrics, Elsevier, vol. 231(1), pages 148-164.
    2. Gizem Koşar & Cormac O'Dea, 2022. "Expectations Data in Structural Microeconomic Models," NBER Working Papers 30094, National Bureau of Economic Research, Inc.
    3. Ye, Xiaoyang & Zhai, Muxin & Feng, Li & Xie, A’na & Wang, Weimin & Wu, Hongbin, 2022. "Still want to be a doctor? Medical student dropout in the era of COVID-19," Journal of Economic Behavior & Organization, Elsevier, vol. 195(C), pages 122-139.
    4. Stephane Bonhomme & Angela Denis, 2023. "Estimating Individual Responses when Tomorrow Matters," Papers 2310.09105, arXiv.org, revised May 2024.
    5. Pamela Giustinelli, 2022. "Expectations in Education: Framework, Elicitation, and Evidence," Working Papers 2022-026, Human Capital and Economic Opportunity Working Group.
    6. Aucejo, Esteban M. & French, Jacob & Ugalde Araya, Maria Paola & Zafar, Basit, 2020. "The impact of COVID-19 on student experiences and expectations: Evidence from a survey," Journal of Public Economics, Elsevier, vol. 191(C).
    7. Yifan Gong & Todd Stinebrickner & Ralph Stinebrickner, 2020. "Perceived and actual option values of college enrollment," Journal of Applied Econometrics, John Wiley & Sons, Ltd., vol. 35(7), pages 940-959, November.
    8. Favara, Marta & Freund, Richard & Perez-Alvarez, Marcello, 2023. "What If It Never Happened? Subjective Treatment Effects of a Negative Shock on Youth Labour Market Outcomes in Developing Countries," IZA Discussion Papers 16417, Institute of Labor Economics (IZA).

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    JEL classification:

    • C21 - Mathematical and Quantitative Methods - - Single Equation Models; Single Variables - - - Cross-Sectional Models; Spatial Models; Treatment Effect Models
    • C83 - Mathematical and Quantitative Methods - - Data Collection and Data Estimation Methodology; Computer Programs - - - Survey Methods; Sampling Methods
    • D84 - Microeconomics - - Information, Knowledge, and Uncertainty - - - Expectations; Speculations
    • J26 - Labor and Demographic Economics - - Demand and Supply of Labor - - - Retirement; Retirement Policies

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