The European Journal of Health Economics

, Volume 15, Issue 1, pp 41–55 | Cite as

Willingness-to-accept reductions in HIV risks: conditional economic incentives in Mexico

  • Omar Galárraga
  • Sandra G. Sosa-RubíEmail author
  • César Infante
  • Paul J. Gertler
  • Stefano M. Bertozzi
Original Paper


The objective of this study was to measure willingness-to-accept (WTA) reductions in risks for HIV and other sexually transmitted infections (STI) using conditional economic incentives (CEI) among men who have sex with men (MSM), including male sex workers (MSW) in Mexico City. A survey experiment was conducted with 1,745 MSM and MSW (18–25 years of age) who received incentive offers to decide first whether to accept monthly prevention talks and STI testing; and then a second set of offers to accept to stay free of STIs (verified by quarterly biological testing). The survey used random-starting-point and iterative offers. WTA was estimated with a maximum likelihood double-bounded dichotomous choice model. The average acceptance probabilities were: 73.9 % for the monthly model, and 80.4 % for the quarterly model. The incentive-elasticity of participation in the monthly model was 0.222, and 0.515 in the quarterly model. For a combination program with monthly prevention talks, and staying free of curable STI, the implied WTA was USD$ 288 per person per year, but it was lower for MSW: USD$ 156 per person per year. Thus, some of the populations at highest risk of HIV infection (MSM and MSW) seem well disposed to participate in a CEI program for HIV and STI prevention in Mexico. The average WTA estimate is within the range of feasible allocations for prevention in the local context. Given the potential impact, Mexico, a leader in conditional cash transfers for human development and poverty reduction, could extend that successful model to targeted HIV/STI prevention.


Willingness-to-accept Conditional economic incentive HIV/AIDS and STI prevention Contingency management/conditional cash transfer Mexico 

JEL Classification

I18 O15 C93 C33 C35 



Useful comments were provided by Jim Berry, Will Dow, Jason Fletcher, Ralph Gonzales, Sandi McCoy, Kevin Volpp, two anonymous referees, and participants at seminars (Mexican School of Public Health, University of California-San Francisco, University of Pennsylvania, Yale University, and University of North Carolina-Chapel Hill) and conferences (7th World Congress of the International Health Economics Association-iHEA—3rd biennial American Society of Health Economists-ASHE—and the XVIII AIDS International Conference). We particularly thank the survey respondents in Mexico City; as well as Luis Pozo-Urquizo, Paola Olivieri, Edgar Ávila and Moisés Calderón of La Manta de México for their involvement in data collection and field work. Research assistance was provided by Fernando Alarid-Escudero. The questionnaire was programmed into the hand-held devices by Edgar Díaz and his team at CEO/Mexico. Alejandro López-Feldman provided additional background material to adapt the Stata ado file “doubleb.” The project benefitted from input of faculty and staff at the Institute of Business and Economic Research (IBER) and the Experimental Social Science Laboratory (X-Lab) at UC Berkeley. We gratefully acknowledge funding from the US National Institutes of Health/Fogarty International Center (Grant No. K01-TW008016-04 PI: Galárraga); and Mexican National Center for HIV/AIDS Control and Prevention (CENSIDA, Prevention Grant 2008).

Supplementary material

10198_2012_447_MOESM1_ESM.docx (106 kb)
Supplementary material 1 (DOCX 106 kb)


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Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Omar Galárraga
    • 1
    • 2
  • Sandra G. Sosa-Rubí
    • 2
    Email author
  • César Infante
    • 3
  • Paul J. Gertler
    • 4
  • Stefano M. Bertozzi
    • 2
    • 5
    • 6
  1. 1.Department of Health Services, Policy and PracticeBrown UniversityProvidenceUSA
  2. 2.Center for Evaluation Research and Surveys, Division of Health EconomicsNational Institute of Public Health (INSP)CuernavacaMexico
  3. 3.Center for Health Systems ResearchNational Institute of Public Health (INSP)CuernavacaMexico
  4. 4.Haas School of Business, School of Public HealthUniversity of CaliforniaBerkeleyUSA
  5. 5.Bill and Melinda Gates FoundationSeattleUSA
  6. 6.Department of Global HealthUniversity of WashingtonSeattleUSA

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