"The Health Effects of Cesarean Delivery for Low-Risk First Births"

Abstract: Cesarean delivery for low-risk pregnancies is generally associated with worse health outcomes for infants and mothers. The interpretation of this correlation, however, is confounded by potential selectivity in the choice of birth mode. We use birth records from California, merged with hospital and emergency department (ED) visits for infants and mothers in the year after birth, to study the casual health effects of cesarean delivery for low-risk first births. Building on McClellan, McNeil, and Newhouse (1994), we use the relative distance from a mother's home to hospitals with high and low c-section rates as an instrument for c-section.  We show that relative distance is a strong predictor of c-section but is orthogonal to many observed risk factors, including birth weight and indicators of prenatal care.  Our IV estimates imply that cesarean delivery causes a relatively large increase in ED visits of the infant, mainly due to acute respiratory conditions. We find no significant effects on mothers’ hospitalizations or ED use after birth, or on subsequent fertility, but we find a ripple effect on second birth outcomes arising from the high likelihood of repeat c-section. Offsetting these morbidity effects, we find that delivery at a high c-section hospital leads to a significant reduction in infant mortality, driven by lower death rates for newborns with high rates of pre-determined risk factors.

"A re-appraisal of thinking on and the empirical evaluation of migration theories"

Abstract: Over the last quarter Century, there has been considerable efforts to systematize knowledge on and empirically test the drivers of population mobility around a set of eight theories that either explain the initiation or continuation of international labor migration flows. In this presentation, I provide a reflection aimed at furthering theoretical development and empirical testing of these theories. I do so by: (1) providing more specific guidance on how the different theories’ overlapping scales of influence interrelate more specifically than examined in prior work; (2) arguing for a more complete formulation of some of these theories to better explain contemporary immigration flows; and (3) discussing whether/how these theories can help bridge the understanding of the “drivers” of internal vs. international migration, and of labor vs. other kinds of mobility, including some forms of forced displacement. Throughout, I also discuss how the quantitative testing of these theories has fallen into pitfalls of both thinking measurement, which have likely led to a misattribution of the relative importance of some theories, suggesting some refinements on the empirical validation of and the more general use of these theories in guiding empirical analysis going forward.
*Co-sponsored with the Center for the Study of International Migration and the Center for Mexican Studies