The Determinants of Birthweight: Addressing Potential Sample Selection Bias from Babies Who Are Not Weighed at Birth

• Main Author: Wahyuni, Heni
• Format: Conference or Workshop Item PeerReviewed
• Language: English
• Published: 2016
• Subjects: Microeconomic Theory
• Online Access: https://repository.ugm.ac.id/135986/1/Balancing%20Indonesia%20Economy%20C.60001.pdf; https://repository.ugm.ac.id/135986/
• Institution: Universitas Gadjah Mada

Introduction The empirical literature reviewed with regard to the infant health production function has focused on the issues relating to endogeneity and sample selection biases, caused by unobserved health heterogeneity and the pregnancy-resolution decision (Liu 1998; ROllS, Jewell & Brown 2004). The first bias relates to endogeneity of prenatal care, while the second, in existing studies, arises from a given woman's decision to abort or continue her pregnancy. Specifically, unobservable factors that may influence a woman's decision to proceed with the pregnancy or abort are factors that are also likely to influence her use of prenatal care and birth outcomes, particularly birthweight. Sample selection bias relating to the decision to abort is unlikely to be a problem in Indonesia, where abortion is socially unacceptable and only conducted for medical reasons. There is a potential for selection bias, however, due to non-random missing information on birthweight. The potential sample selection bias that arises from birthweight being missing for some babies (those not weighed at birth) is a common issue in developing countries and generally does not occur in studies of birthweight in developed countries. If the birth weight information in the sample is not missing at random, however, the analysis of the determinants of birthweight(without considering unreported birthweight) will be biased (Heckman 1979). This represents a possible sample selection issue, given that the data on a key variable (birthweight) are availableonly for a subset of the population, who are not weighed at birth. This is often referred to as incidental truncation (Wooldridge 2002, p. 552).