Hostname: page-component-78c5997874-xbtfd Total loading time: 0 Render date: 2024-11-13T11:31:27.617Z Has data issue: false hasContentIssue false
  • English
  • Français

Comparison of four contingent valuation methods to estimate the economic value of a pneumococcal vaccine in Bangladesh

Published online by Cambridge University Press:  01 October 2008

Rebekah R. Heinzen  and
John F. P. Bridges
Rebekah R. Heinzen
Affiliation:
Johns Hopkins Bloomberg School of Public Health
John F. P. Bridges
Affiliation:
Johns Hopkins Bloomberg School of Public Health
Get access Rights & Permissions [Opens in a new window]

Abstract

Objectives: To compare four contingent valuation elicitation methods as a means to estimate the value of a pneumococcal vaccine in Bangladesh and to test if the elicitation methods are subject to bias and if they produce valid responses.

Methods: Three hundred sixty-one households with at least one child under 5 years of age were recruited in Dhaka, Bangladesh. Subjects were cluster-randomized to various elicitation methods: open-ended, dichotomous choice (at one of two asking prices), payment card (one of two cards with differing ranges). The dichotomous choice method was then followed up with a bidding game methodology, with the dichotomous choice price acting as the starting price for the bidding game. Analysis focused on summary statistics, demand curve estimation and multivariate regression analysis to test for validity and bias.

Results: Thirty-one households refused to participate, leaving a total of 330 participating households (a 91.4 percent response rate). Willingness to pay estimates varied significantly across the methods (p < .001), with average estimates varying between $2.34 and $18 (US). The open-ended elicitation method was found to produce highly inflated values that were insensitive to construct validity tests. The dichotomous choice method produced quantity (demand) estimates rather than value estimates, and there was some evidence of yea saying. The payment card elicitation method was found to be affected by range bias. The bidding game elicitation method was found to be less sensitive to starting point bias and yea-saying.

Conclusions: Different elicitation format do give rise to different demand curves; however, this may be partially due to the fact that they do not measure the same outcome. For example, the dichotomous choice format produces a demand curve, while the payment card, open-ended and bidding game produce inverse demand curves. All formats are prone to multiple biases. When choosing an elicitation format, it is important to first consider the purpose and use of the data. Each elicitation method has strengths and weaknesses and can be used for different purposes in technology assessment.

Keywords

Social valuesVaccinesDeveloping countriesEvaluation methodologyHealth services needs and demand
Type
RESEARCH REPORTS
Information
International Journal of Technology Assessment in Health Care , Volume 24 , Issue 4 , October 2008 , pp. 481 - 487
Copyright
Copyright © Cambridge University Press 2008

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Arifeen, SE, Akhter, T, Chowdhury, HR, et al. Causes of death in children under five years of age. In: National Institute of Population Research and Training, Mitra and Associates, Macro, ORC, eds. Bangladesh demographic and health survey 2004. Dhaka: National Institute of Population Research and Training (NIPORT); 2005:125–133.Google Scholar
2. Arrow, K, Solow, R, Portney, PR, et al. Report of the NOAA panel on contingent valuation. Federal Register. 1993;58:08/01/07-4601-14. http://www.darp.noaa.gov/library/pdf/cvblue.pdf. Accessed 11 January 1993.Google Scholar
3. Blamey, RK, Bennett, JW, Morrison, MD. Yea-saying in contingent valuation surveys. Land Econ. 1999;75:126–141.CrossRefGoogle Scholar
4. Blumenschein, K, Johannesson, M, Blomquist, GC, Liljas, B, O'Conor, RM. Experimental results on expressed certainty and hypothetical bias in contingent valuation. South Econ J. 1998;65:169–177.Google Scholar
5. Boyle, KJ, Johnson, FR, McCollum, DW, et al. Valuing public goods: Discrete versus continuous contingent-valuation responses. Land Econ. 1996;72:381–396.CrossRefGoogle Scholar
6. Bridges, J. Stated preference methods in health care evaluation: An emerging methodological paradigm in health economics. Appl Health Econ Health Policy. 2003;2:213–224.Google ScholarPubMed
7. Bridges, J, Jones, C. Patient based health technology assessment: A vision of what might one day be possible. Int J Technol Assess Health Care. 2007;23:30–35.CrossRefGoogle Scholar
8. Cutts, FT, Zaman, SM, Enwere, G, et al. Efficacy of nine-valent pneumococcal conjugate vaccine against pneumonia and invasive pneumococcal disease in The Gambia: Randomised, double-blind, placebo-controlled trial. Lancet. 2005;365:1139–1146.CrossRefGoogle ScholarPubMed
9. Frew, EJ, Whynes, DK, Wolstenholme, JL. Eliciting willingness to pay: Comparing closed-ended with open-ended and payment scale formats. Med Decis Making. 2003;23:150–159.CrossRefGoogle ScholarPubMed
10. Frew, EJ, Wolstenholme, JL, Whynes, DK. Comparing willingness-to-pay: Bidding game format versus open-ended and payment scale formats. Health Policy. 2004;68:289–298.CrossRefGoogle ScholarPubMed
11. Frykblom, P. Hypothetical question modes and real willingness to pay. J Environ Econ Manage. 1997;34:275–287.CrossRefGoogle Scholar
12. Graff Zivin, J, Bridges, J. Addressing risk preferences in cost-effectiveness analyses. Appl Health Econ Health Policy. 2002;1:135–139.Google Scholar
13. Günther, OH, König, HH. Decision makers' and scientists' opinion about contingent valuation and choice experiments for measuring willingness to pay in health care: Results from a survey in Germany. Int J Technol Assess Health Care. 2006;22:351–361.CrossRefGoogle ScholarPubMed
14. Herbild, L, Gyrd-Hansen, D, Bech, M. Patient preferences for pharmacogenetic screening in depression. Int J Technol Assess Health Care. 2008;24:96–103.CrossRefGoogle ScholarPubMed
15. Johannesson, M, Jonsson, B, Borgquist, L. Willingness to pay for antihypertensive therapy-results of a Swedish pilot study. J Health Econ. 1991;10:461–474.CrossRefGoogle ScholarPubMed
16. Kauder, E. Genesis of the marginal utility theory: From Aristotle to the end of the eighteenth century. Econ J. 1953;63:638–650.Google Scholar
17. Klose, T. The contingent valuation method in health care. Health Policy. 1999;47:97–123.CrossRefGoogle ScholarPubMed
18. Lindholm, L, Rosén, M, Hellsten, G. Are people willing to pay for a community-based preventive program. Int J Technol Assess Health Care. 1994;10:317–324.CrossRefGoogle ScholarPubMed
19. Mill, JS. Principles of political economy: With some of their applications to social philosophy. London: John W. Parker; 1848.Google Scholar
20. O'Brien, B, Gafni, A. When do ‘dollars’ make sense? towards a conceptual framework for contingent valuation studies in health care. Med Decis Making. 1996;16:288–299.CrossRefGoogle Scholar
21. Onwujekwe, O. Searching for a better willingness to pay elicitation method in rural Nigeria: The binary question with follow-up method versus the bidding game technique. Health Econ. 2001;10:147–158.CrossRefGoogle ScholarPubMed
22. Onwujekwe, O, Uzochukwu B. Stated and actual altruistic willingness to pay for insecticide-treated nets in Nigeria: Validity of open-ended and binary with follow-up questions. Health Econ. 2004;13:477–492.CrossRefGoogle ScholarPubMed
23. Ryan, M, Scott, D, Donaldson, C. Valuing health care using willingness to pay: A comparison of the payment card and dichotomous choice methods. J Health Econ. 2004;23:237–258.CrossRefGoogle Scholar
24. Whynes, DK, Frew EJ, Wolstenholme JL. Willingness-to-pay and demand curves: A comparison of results obtained using different elicitation formats. Int J Health Care Finance Econ. 2005;5:369–386.CrossRefGoogle ScholarPubMed
25. Whynes, DK, Wolstenholme, JL, Frew, E. Evidence of range bias in contingent valuation payment scales. Health Econ. 2004;13:183–190.CrossRefGoogle ScholarPubMed
26. Yeung, RY, Smith, RD. Can we use contingent valuation to assess the demand for childhood immunisation in developing countries?: A systematic review of the literature. Appl Health Econ Health Policy. 2005;4:165–173.CrossRefGoogle ScholarPubMed