Heterogeneous impact of the “Seguro Popular” program on the utilization of obstetrical services in Mexico, 2001–2006: A multinomial probit model with a discrete endogenous variable

Abstract

Objective

We evaluated the impact of Seguro Popular (SP), a program introduced in 2001 in Mexico primarily to finance health care for the poor. We focused on the effect of household enrollment in SP on pregnant women’s access to obstetrical services, an important outcome measure of both maternal and infant health.

Data

We relied upon data from the cross-sectional 2006 National Health and Nutrition Survey (ENSANUT) in Mexico. We analyzed the responses of 3890 women who delivered babies during 2001–2006 and whose households lacked employer-based health care coverage.

Methods

We formulated a multinomial probit model that distinguished between three mutually exclusive sites for delivering a baby: a health unit specifically accredited by SP; a non-SP-accredited clinic run by the Department of Health (Secretaría de Salud, or SSA); and private obstetrical care. Our model accounted for the endogeneity of the household’s binary decision to enroll in the SP program.

Results

Women in households that participated in the SP program had a much stronger preference for having a baby in a SP-sponsored unit rather than paying out of pocket for a private delivery. At the same time, participation in SP was associated with a stronger preference for delivering in the private sector rather than at a state-run SSA clinic. On balance, the Seguro Popular program reduced pregnant women’s attendance at an SSA clinic much more than it reduced the probability of delivering a baby in the private sector. The quantitative impact of the SP program varied with the woman’s education and health, as well as the assets and location (rural vs. urban) of the household.

Conclusions

The SP program had a robust, significantly positive impact on access to obstetrical services. Our finding that women enrolled in SP switched from non-SP state-run facilities, rather than from out-of-pocket private services, is important for public policy and requires further exploration.

Introduction

This paper contributes to three important strands in the health economics literature. First, we add to the emerging body of knowledge on the impacts of novel public policies to finance the health care of the poor in developing economies (Gaviria et al., 2006, Trujillo et al., 2005, Wagstaff, 2007, Wagstaff et al., 2007), including recent innovative interventions in Mexico (Knaul and Frenk, 2005, Frenk et al., 2003, Gakidou et al., 2006, Sepúlveda et al., 2006). We find that the recently established “Seguro Popular” (SP) (or “People’s Insurance”) program in Mexico has had a robust, significantly positive effect on the access of poor women to obstetrical care, an important outcome measure of maternal and infant health.

Second, we add to the growing literature on the use of multinomial discrete choice models of the selection of health care providers, including Schwartz et al. (1988) in the setting of the Philippines, Akin et al. (1995) in Nigeria, Bolduc et al. (1996) in Benin, and Leonard (2007) in Tanzania, as well as recent path-breaking work on multi-equation models involving discrete variables (Balia and Jones, 2004, Deb et al., 2006). We formulate a multinomial probit model that distinguishes between three mutually exclusive sites for delivering a baby: a health unit specifically accredited by Seguro Popular; a non-SP-accredited clinic run by the Department of Health (Secretaría de Salud, or SSA); and private obstetrical services. In what appears to be the first instance of such a technique, we then modify the standard multinomial probit model to explicitly account for the possible endogeneity of the household’s binary decision to participate in Seguro Popular. Women in households that participated in the SP program, we find, had a much stronger preference for having a baby in a SP-sponsored unit rather than paying out of pocket for a private delivery. At the same time, participation in SP was associated with a stronger preference for delivering in the private sector rather than at an SSA-sponsored clinic. On balance, the Seguro Popular program reduced pregnant women’s attendance at an SSA-sponsored clinic much more than it reduced the probability of delivering a baby in the private sector.

Third, we contribute to the nascent but expanding body of work on the heterogeneous impacts of policy interventions in the developing world, including the effect of antiretroviral treatment on labor force participation in Western Kenya (Thirumurthy et al., 2006), the effect of conditional cash transfers on schooling and nutrition in Nicaragua (Dammert, 2007) and Mexico (Djebbari and Smith, 2005, Chávez-Martín del Campo, 2006). Here, we find that the quantitative impact of the SP program varied with the woman’s education and health, as well as the assets and location (rural vs. urban) of the household.

In Section 2, we review the problem of access to obstetric care for poor women in Mexico, the basic structure of the Mexican health care system, and the introduction of Seguro Popular in 2001. In Section 3, we describe an econometric model of discrete household decision-making concerning the use obstetrical services. The model captures the possibility that a demand-side subsidy such as Seguro Popular can affect the household’s relative ranking of the three obstetric service sites. We explicitly take into account the potential endogeneity of the decision to participate in Seguro Popular, and describe our strategy for evaluating heterogeneous impacts. Section 4 describes our database, the 2006 National Survey of Health and Nutrition (Encuesta Nacional de Salud y Nutrición, or ENSANUT; see Instituto Nacional de Salud Pública, 2006). Section 5 details our empirical results. Section 6 summarizes our findings, discusses the limitations of our research, and considers its implications for public policy and future research on health policy in developing economies.