IDEAS home Printed from https://ideas.repec.org/p/ecm/nasm04/104.html
   My bibliography  Save this paper

Testing for Placebo Effects Using Data from Blinded, Randomized Controlled Trials

Author

Listed:
  • Anup Malani

Abstract

This paper proposes a test for the existence of placebo effects, as described by the so-called expectancy theory. This theory, which is the dominant medical theory of how placebo effects operate, posits that health outcomes rise in individuals' beliefs about the probability that they are getting a beneficial treatment and their beliefs about the efficacy of that treatment. Blinded, randomized, controlled trials provide near-perfect environments in which to test this theory because they offer objective, controlled manipulations of subjects' beliefs about treatment. If the expectancy theory is correct, outcomes in trials offering a higher probability of receiving an experimental treatment should be superior to outcomes in trials offering a lower probability of receiving that treatment, conditional on treatment assignment. The paper applies this test to data from over 200 trials of anti-ulcer medications and finds robust evidence of placebo effects in trials of H2-blockers (e.g., Zantac, Tagamet and Pepcid) and of proton-pump inhibitors (e.g., Prilosec, Nexium, and Prevacid). Indeed, trials of H2-blockers manifest placebo effects that are 50 percent as large as the physiological effects of these medications. Because placebo effects are not confined to clinical trials, this result suggests that the standard difference-in-means estimator of treatment effects may seriously underestimate the efficacy of anti-ulcer medications

Suggested Citation

  • Anup Malani, 2004. "Testing for Placebo Effects Using Data from Blinded, Randomized Controlled Trials," Econometric Society 2004 North American Summer Meetings 104, Econometric Society.
  • Handle: RePEc:ecm:nasm04:104
    as

    Download full text from publisher

    File URL: http://repec.org/esNASM04/up.5431.1074096894.pdf
    Download Restriction: no
    ---><---

    References listed on IDEAS

    as
    1. Mark Yuying An, 1996. "Log-concave Probability Distributions: Theory and Statistical Testing," Game Theory and Information 9611002, University Library of Munich, Germany.
    2. Heckman, James J & Honore, Bo E, 1990. "The Empirical Content of the Roy Model," Econometrica, Econometric Society, vol. 58(5), pages 1121-1149, September.
    Full references (including those not matched with items on IDEAS)

    Most related items

    These are the items that most often cite the same works as this one and are cited by the same works as this one.
    1. Wang, Jin, 2021. "Do birds of a feather flock together? Platform’s quality screening and end-users’ choices theory and empirical study of online trading platforms," International Journal of Industrial Organization, Elsevier, vol. 75(C).
    2. James J. Heckman, 1991. "Randomization and Social Policy Evaluation Revisited," NBER Technical Working Papers 0107, National Bureau of Economic Research, Inc.
    3. Lanot, Gauthier & Walker, Ian, 1998. "The union/non-union wage differential: An application of semi-parametric methods," Journal of Econometrics, Elsevier, vol. 84(2), pages 327-349, June.
    4. Paul Ellickson & Sanjog Misra, 2012. "Enriching interactions: Incorporating outcome data into static discrete games," Quantitative Marketing and Economics (QME), Springer, vol. 10(1), pages 1-26, March.
    5. Susan Athey & Scott Stern, 1998. "An Empirical Framework for Testing Theories About Complimentarity in Organizational Design," NBER Working Papers 6600, National Bureau of Economic Research, Inc.
    6. Burgess, Simon & Lane, Julia & Stevens, David, 1997. "Jobs, Workers and Changes in Earnings Dispersion," CEPR Discussion Papers 1714, C.E.P.R. Discussion Papers.
    7. Heckman, James, 2001. "Accounting for Heterogeneity, Diversity and General Equilibrium in Evaluating Social Programmes," Economic Journal, Royal Economic Society, vol. 111(475), pages 654-699, November.
    8. Chakravarty, Surajeet & Kaplan, Todd R. & Myles, Gareth, 2018. "When costly voting is beneficial," Journal of Public Economics, Elsevier, vol. 167(C), pages 33-42.
    9. McLaughlin, Kenneth J & Bils, Mark, 2001. "Interindustry Mobility and the Cyclical Upgrading of Labor," Journal of Labor Economics, University of Chicago Press, vol. 19(1), pages 94-135, January.
    10. Vishal Kamat, 2017. "Identification of Program Access Effects with an Application to Head Start," Papers 1711.02048, arXiv.org, revised Oct 2020.
    11. Peter Kuhn & Marie-Claire Villeval, 2011. "Do Women Prefer a Co-operative Work Environment?," Working Papers 1127, Groupe d'Analyse et de Théorie Economique Lyon St-Étienne (GATE Lyon St-Étienne), Université de Lyon.
    12. Christopher Taber & Rune Vejlin, 2020. "Estimation of a Roy/Search/Compensating Differential Model of the Labor Market," Econometrica, Econometric Society, vol. 88(3), pages 1031-1069, May.
    13. Arnaud Costinot & Jonathan Vogel, 2010. "Matching and Inequality in the World Economy," Journal of Political Economy, University of Chicago Press, vol. 118(4), pages 747-786, August.
    14. Akee, Randall K. Q., 2007. "Who Leaves and Who Returns? Deciphering Immigrant Self-Selection from a Developing Country," IZA Discussion Papers 3268, Institute of Labor Economics (IZA).
    15. James J. Heckman, 1991. "Randomization and Social Policy Evaluation Revisited," NBER Technical Working Papers 0107, National Bureau of Economic Research, Inc.
    16. James J. Heckman, 2008. "Econometric Causality," International Statistical Review, International Statistical Institute, vol. 76(1), pages 1-27, April.
    17. Monika Köppl-turyna & Michael Christl, 2018. "Returns to Skills or Returns to Tasks? A Comment on Hanushek et al. (2015)," Economics Bulletin, AccessEcon, vol. 38(2), pages 783-790.
    18. Finicelli, Andrea & Pagano, Patrizio & Sbracia, Massimo, 2013. "Ricardian selection," Journal of International Economics, Elsevier, vol. 89(1), pages 96-109.
    19. Andrén, Thomas & Gustafsson, Björn, 2002. "Income effects from labor market training programs in Sweden during the 80's and 90's," Working Paper Series 2002:15, IFAU - Institute for Evaluation of Labour Market and Education Policy.
    20. Daniel Diermeier & Michael Keane & Antonio Merlo, 2005. "A Political Economy Model of Congressional Careers," American Economic Review, American Economic Association, vol. 95(1), pages 347-373, March.

    More about this item

    Keywords

    Placebo effects; randomized controlled trials; informed consent; blinding; self-selection; expected utility; ulcer;
    All these keywords.

    JEL classification:

    • I10 - Health, Education, and Welfare - - Health - - - General
    • C93 - Mathematical and Quantitative Methods - - Design of Experiments - - - Field Experiments

    Statistics

    Access and download statistics

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:ecm:nasm04:104. See general information about how to correct material in RePEc.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Christopher F. Baum). General contact details of provider: https://edirc.repec.org/data/essssea.html .

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    If CitEc recognized a reference but did not link an item in RePEc to it, you can help with this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service hosted by the Research Division of the Federal Reserve Bank of St. Louis . RePEc uses bibliographic data supplied by the respective publishers.