Are there differences between unconditional and conditional demand estimates? implications for future research and policy

Hidayat, Budi (2007): Are there differences between unconditional and conditional demand estimates? implications for future research and policy. Published in: Cost Effectiveness and Resource Allocation , Vol. 6, (5 August 2008)

Abstract

Background: Estimations of the demand for healthcare often rely on estimating the conditional probabilities of being ill. Such estimate poses several problems due to sample selectivity problems and an under-reporting of the incidence of illness. This study examines the effects of health insurance on healthcare demand in Indonesia, using samples that are both unconditional and conditional on being ill, and comparing the results. Methods: The demand for outpatient care in three alternative providers was modeled using a multinomial logit regression for samples unconditional on being ill (N = 16485) and conditional on being ill (N = 5055). The ill sample was constructed from two measures of health status – activity of daily living impairments and severity of illness – derived from the second round of panel data from the Indonesian Family Life Survey. The recycling prediction method was used to predict the distribution of utilization rates based on having health insurance and income status, while holding all other variables constant. Results: Both unconditional and conditional estimates yield similar results in terms of the direction of the most covariates. The magnitude effects of insurance on healthcare demand are about 7.5% (public providers) and 20% (private providers) higher for unconditional estimates than for conditional ones. Further, exogenous variables in the former estimates explain a higher variation of the model than that in the latter ones. Findings confirm that health insurance has a positive impact on the demand for healthcare, with the highest effect found among the lowest income group. Conclusion: Conditional estimates do not suffer from statistical selection bias. Such estimates produce smaller demand effects for health insurance than unconditional ones do. Whether to rely on conditional or unconditional demand estimates depends on the purpose of study in question. Findings also demonstrate that health insurance programs significantly improve access to healthcare services, supporting the development of national health insurance programs to address under-utilization of formal healthcare in Indonesia.

• Item Type: MPRA Paper
• Language: English
• Keywords: health care demand; conditional estimates; unconditional estimates; health insurance
• Subjects: C - Mathematical and Quantitative Methods > C5 - Econometric Modeling > C53 - Forecasting and Prediction Methods ; Simulation Methods; I - Health, Education, and Welfare > I1 - Health > I18 - Government Policy ; Regulation ; Public Health; C - Mathematical and Quantitative Methods > C3 - Multiple or Simultaneous Equation Models ; Multiple Variables > C35 - Discrete Regression and Qualitative Choice Models ; Discrete Regressors ; Proportions

References

Sauerborn R, Nougtara A, Latimer E: The elasticity of demand for health care in Burkina Faso: differences across age and income groups. Health Policy and Planning 1994, 9:185-192.

Fabricant SJ, Kamara CW, Mills A: Why the poor pay more: household curative expenditures in rural Sierra Leone. International Journal of Health Planning and Management 1999, 14:179-199.

Baltussen RMP, Yé Y, Haddad S, Sauerborn R: Perceived quality of care of primary health care services in Burkina Faso. Health Policy and Planning 2002, 17:42-48.

Hidayat B, Thabrany H, Dong H, Sauerborn R: The effects of mandatory health insurance on equity in access to outpatient care in Indonesia. Health Policy and Planning 2004, 19:322-335.

Akin JS, Guilkey DK, Hutchinson P, McIntosh : Price elasticity of demand for curatives health care with control for sample selectivity on endogenous illness: An analysis for Sri Lanka. Health Economics 1998, 7:509-531.

Dow WH: Unconditional demand for health care in Cote d'Ivoire: does selection on health status matter? In LSMS Working Paper No. 127. Washington DC: The World Bank; 1996.

Sauerborn R, Nougtara A, Hien M, Diesfeld HJ: Seasonal variations of household costs of illness in Burkina Faso. Social Science and Medicine 1996, 43:281-290.

Hidayat B: Modelling the effects of health insurance on healthcare demand in Indonesia. PhD thesis. Ruprecht-Karls-University of Heidelberg, Department of Public Health and Tropical Medicine; 2004.

United Nation Statistics Division: Demographic, social and housing statistics. 2007.

Waters H, Saadah F, Pradhan M: The impact of the 1997–98 East Asian economic crisis in health and health care in Indonesia. Health Policy and Planning 2003, 18:172-181.

Frankenberg E, Karoly L: The 1993 Indonesian Family Life Survey: overview and field report. RAND Corporation, USA; 1995.

Frankenberg E, Thomas D: The Indonesia Family Life Survey (IFLS): Study design and results from waves 1 and 2. RAND Corporation, USA; 2000.

Greene W: Econometric analysis. 3rd edition. Prentice-Hall: Englewood Cliffs NJ; 1997.

Yip W, Wang H, Liu Y: Determinants of patient choice of medical provider: a case study in rural China. Health Policy and Planning 1998, 13:311-322.

Stata Corporation: Stata statistical software Release 7.0. Texas: College Station; 2001.

Thabrany H, Pujianto : Health Insurance and access to health care. The Journal of the Indonesian Medical Association 2000, 50:282-289.

Waters HR: Measuring the impact of health insurance with correction for selection bias: a case study of Ecuador. Health Economics 1999, 8:473-483.

Schllhron M: The effect of variable health insurance deductibles on the demand for physician visits. Health Economics 2001, 10:441-456.

Trujillo AJ: Medical care use and selection in a social health insurance with an equalization fund: evidence from Colombia. Health Econ 2002, 12(3):231-246.

Baum CF, Schaffer ME, Stillman S: Instrumental variables and GMM: estimation and testing. Stata Journal 2003, 3:1-31.

Heckman J: Sample selection bias as a specification error. Econometrica 1979, 47:153-161.

Ven W, van Pragg B: The demand for deductibles in private health insurance: a probit model with sample selection. Journal of Econometrics 1981, 17:229-252.

Waters HR: Measuring equity in access to health care. Social Science and Medicine 2000, 51:599-612.

Feldstein PJ: Health care economics. 4th edition. New York Albany; 1993.

Yip W, Berman P: Targeted health insurance in a low income country and its impact on access and equity in access: Egypt's school health insurance. Health Economics 2001, 10:207-220.

Jowett M, Deolalikar A, Martinsson P: Health insurance and treatment seeking behaviour: evidence from a low-income country. Health Economics 2004, 13:845-857.

Pradhan M, Saadah F, Sparrow R: Did the health card program ensure access to medical care for the poor during Indonesia's economic crisis? World Bank Economic Review 2007, 21:125-150.