The causal impact of cesarean sections on neonatal health

This post has been written by Ana Costa Ramón and Ana Rodríguez González.  Both are PhD candidates at the Economics department of Universitat Pompeu Fabra.

In recent decades there has been an increasing concern about the rise of cesarean section births. Among OECD countries in 2013, on average more than 1 out of 4 births involved a c-section (OECD, 2013), being one of the most commonly performed surgeries. Cesarean sections, performed when needed and under standard quality measures, save lives. However, unnecessary c-sections not only impose significant costs for the health system but can also negatively impact infant health.  Previous literature has found cesarean sections to be associated with several adverse health outcomes for the newborn (Grivell & Dodd, 2011) and with worse later infant health(Keag, Norman, & Stock, 2018). However, most of the studies that came to these conclusions compared mothers who gave birth vaginally with those that had a cesarean section, and this may produce biased results: mothers who give birth by c-section are likely to have different characteristics from those who have vaginal births, and this may influence the health outcomes of the child and the mother after delivery.

In a recent paper, published in the Journal of Health Economics (Costa-Ramón, Rodríguez-González, Serra-Burriel, & Campillo-Artero, 2018), we contribute to fill this gap by providing causal evidence of the impact of avoidable cesarean birth on neonatal health. To do so, we exploit variation in the probability of having a c-section that is unrelated to maternal characteristics: variation by time of day.

In particular, using data from four public hospitals in Spain, we first document that the probability of having an unplanned c-section is higher in the early hours of the night (from 11 pm to 4 am) and that this is not driven by different characteristics of mothers giving birth during these times. Figure 1 shows the c-section rate at different times of day in our sample. We can observe that the distribution of unscheduled c-sections by time of birth is not uniform. Births that take place between 11 pm and 4 am are around 6 percentage points more likely to be by cesarean.

Csections

Notes: The figure represents the proportion of unplanned c-sections by time of day over the sample of unplanned c-sections and vaginal births. Sample is restricted to single births, unscheduled c-sections and vaginal births (excluding breech vaginal babies).

We argue that, given the medical shift structure in public hospitals and the larger time-cost of surveillance implied by vaginal deliveries, doctors’ incentives to perform c-sections in ambiguous cases may be higher during these times. In fact, we are not the first to document peaks in the unplanned c-section rate during the early night. Previous studies interpret this variation as evidence that convenience and doctors’ demand for leisure influence timing and mode of delivery (Brown, 1996; Fraser et al., 1987; Hueston, McClaflin, & Claire, 1996; Spetz, Smith, & Ennis, 2001).

We take advantage of this exogenous variation and use time of day as an instrument for the probability of having an unplanned c-section. This allows us to compare mothers that give birth in the same hospital and have similar observable characteristics, differing only in the time of delivery. Our results suggest that these non-medically indicated c-sections lead to a significant worsening of Apgar scores of approximately one standard deviation, but we do not find effects on more extreme outcomes such as needing reanimation, being admitted to the ICU or on neonatal death. This is an important finding, given that previous studies in the medical literature documented an association between c-sections and an increased risk of serious respiratory morbidity and subsequent admission to neonatal ICU (Grivell & Dodd, 2011). Their findings are consistent with the results of our OLS estimation, suggesting that former analysis might have been capturing the underlying health status of newborns who need a medically necessary cesarean.

A few words on the publication process and media coverage

Given that it was a health-oriented paper, we decided to target a top field journal in health economics. We were very lucky and all the publication process went very fast and smoothly.  We had to revise the paper once and get additional data in order to be able to address some of the reviewers’ comments.

When it was published, with the help of UPF’s communication unit we sent a press release and our paper got attention from the Spanish media.  We knew that it was a controversial topic (especially from the doctors’ perspective) so we chose our words carefully, but still we got some slightly sensationalist headlines.  We learnt the lesson: you have to choose a catchy punchline yourself, or they will pick their own (and you won’t always like it).

Overall, it has been an intense and fruitful experience!

References:

Brown, H. S. (1996). Physician demand for leisure: Implications for cesarean section rates. Journal of Health Economics, 15(2), 233–242. https://doi.org/10.1016/0167-6296(95)00039-9

Costa-Ramón, A. M., Rodríguez-González, A., Serra-Burriel, M., & Campillo-Artero, C. (2018). It’s about time: Cesarean sections and neonatal health. Journal of Health Economics, 59. https://doi.org/10.1016/j.jhealeco.2018.03.004

Fraser, W., Usher, R. H., McLean, F. H., Bossenberry, C., Thomson, M. E., Kramer, M. S., … Power, H. (1987). Temporal variation in rates of cesarean section for dystocia: Does “convenience” play a role? American Journal of Obstetrics and Gynecology, 156(2), 300–304. https://doi.org/http://dx.doi.org/10.1016/0002-9378(87)90272-9

Grivell, R. M., & Dodd, J. M. (2011). Short- and long-term outcomes of cesarean section. Expert Review of Obsetrics and Gynecology, 6(2), 205–216.

Hueston, W. J., McClaflin, R. R., & Claire, E. (1996). {V}ariations in cesarean delivery for fetal distress. The Journal of Family Practice, 43(5), 461–467.

Keag, O. E., Norman, J. E., & Stock, S. J. (2018). Long-term risks and benefits associated with cesarean delivery for mother, baby, and subsequent pregnancies: Systematic review and meta-analysis. PLoS Medicine, 15(1), 1–22. https://doi.org/10.1371/journal.pmed.1002494

OECD. (2013). Health at a Glance 2013: OECD Indicators. Paris: OECD Publishing.

Spetz, J., Smith, M. W., & Ennis, S. F. (2001). Physician Incentives and the Timing of Cesarean Sections: Evidence from California Physician Incentives and the Timing of Cesarean Sections Evidence From California. Source: Medical Care MEDICAL CARE, 39(6), 536–550. https://doi.org/10.1097/00005650-200106000-00003

 

Heterogeneous Inputs, Human Resource Management and Productivity Spillovers: What Do Poultry Farm Workers Have to Say? – Job Market Paper

authorThe following job market paper summary was contributed by Francesco Amodio (Economics ’10 and GPEFM). Francesco is a job market candidate at UPF. He will be available for interviews at the SAEe (Palma de Mallorca, December 11-13) and ASSA (Boston, January 3-5) meetings.

 


Management matters. Differences in management practices can explain a considerable amount of variation in firms’ productivity and performance, both across and within sectors and countries (Bloom and Van Reenen 2007, 2010, 2011). Several studies have shown how human resource management and incentive schemes may affect overall productivity by making the effort choices of coworkers interdependent (Bandiera, Barankay and Rasul 2005, 2007, 2009). In more complex settings, however, workforce management features may interact with production arrangements and jointly determine the overall result of the organization. Understanding the nature of this interplay is of primary importance in the adoption and implementation of productivity-enhancing management practices.

In my job market paper, coauthored with Miguel A. Martinez-Carrasco, we shed light on these issues by focusing on settings where workers produce output by combining their own effort with inputs of heterogeneous quality. This is a common feature of workplaces around the world. For instance, in Bangladeshi garment factories, the characteristics of raw textiles used as inputs affect the productivity of workers. Similarly, the purity level of chemicals affects the productivity of researchers in biological research labs.

Now, suppose we pick a worker and endow her with higher quality inputs, thus increasing her productivity. What happens to the productivity of coworkers around her? Do they exert more effort, or do they shirk? How do human resource management features shape their response?

The setting

In order to answer these questions, we collected data from an egg production plant in Peru. Production is carried out in production units located one next to the other in several sheds. In each production unit, a single worker is assigned as input a batch of laying hens. Workers’ main tasks are to feed the hens, to maintain and clean the facilities, and to collect the eggs. The characteristics of the hens and worker’s effort jointly determine productivity, as measured by the daily number of collected eggs. Figure 1 shows the picture of one shed hosting four production units. Notice how workers in neighboring production units can easily interact and observe each other.

figure

The specific features and logistics of this setting generate the quasi-experiment we need in order to answer the questions of interest. All hens within a given batch have very similar characteristics. When reaching their productive age, they are moved to one production unit and assigned to the corresponding single worker who operates the unit. After approximately 16 months, they reach the end of their productive age and are discarded altogether. The age of hens in the batch exogenously shifts productivity. Indeed, Figure 2 shows the reversed U-shaped relationship that exists between hens’ age and productivity. Perhaps more importantly, the timing of batch replacement varies across production units, generating quasi-random variation in the age of hens assigned to workers.1 We can thus exploit these differences to credibly identify the causal effect of an increase in coworkers’ productivity – as exogenously shifted by coworkers’ hens age – on own productivity, conditional on own hens’ age.

figure

Main Results

We find evidence of negative productivity spillovers. The same worker, handling hens of the same age, is significantly less productive when coworkers in neighboring production units are more productive, with variation in the latter being induced by changes in the age of their own hens. This finding is pictured in Figure 3, which shows that a U-shaped relationship exists between own productivity and coworkers’ hens age. In other words, workers exert less effort and decrease their productivity when coworkers are assigned higher quality inputs.

figure

We also find similar negative effects on output quality, as measured by the fraction of broken and dirty eggs collected over the total number of eggs. Furthermore, we find no effect of an increase in the productivity of coworkers located in non-neighboring production units or in different sheds, suggesting that workers only respond to observed changes in coworkers’ productivity.

The role of HR

Why do workers exert less effort when coworkers’ productivity increases? Our hypothesis is that the way the management processes information on workers’ productivity in evaluating them and taking employment termination decisions generates free ride issues among coworkers. When observed productivity is only a noisy signal of workers’ exerted effort, the management combines available signals and best guesses the level of effort exerted by the worker. Even when observable input characteristics can be netted out, individual signals are still imperfect, and possibly excessively costly to process. The management thus attaches a positive weight to aggregate or average productivity in evaluating a single worker. As a result, workers free ride on each other.

In order to test for this hypothesis, we collected employee turnover data from the same firm. As expected, we find that the likelihood of employment termination is lower the more productive the worker is. More importantly, being next to highly productive workers improves a given worker’s evaluation and diminishes her marginal returns from effort, yielding negative productivity spillovers.

We also find that providing incentives to workers counteracts their tendency to free ride. First, we find no effect of coworkers’ productivity when workers are exposed to piece-rate pay. Second, we collected data on the friendship and social relationship among workers, and find again no effect of coworkers’ productivity when a given worker recognizes any of her coworkers as friends. We interpret this as further evidence that the main result of a negative effect of coworkers’ productivity indeed captures free riding issues, mitigated by the presence of social relationships.

Discussion

Our focus on production inputs and their allocation to working peers represents the main innovation with respect to the previous literature on human resource management and incentives at the workplace. In our case study, the allocation of inputs of heterogeneous quality among workers triggers free riding and negative productivity spillovers among them, generated by the workers’ evaluation and termination policies implemented at the firm.

The analysis of more complex production settings reveals the existence of intriguing patterns of interplay between production arrangements and human resource management practices. Our plan for the next future is to proceed further along this line of inquiry. In a companion paper still work in progress, we investigate both theoretically and empirically how workers influence each other in their choice of inputs while updating information on the productivity of the latter from own and coworkers’ experience.


1 Grouping all observations belonging to the same shed and week and taking residuals, we show that the age of hens assigned to coworkers is orthogonal to the age of own hens. We test this hypothesis in several different ways, addressing the issues arising when estimating within-group correlation among peers’ characteristics (Guryan, Kroft, and Notowidigdo 2009; Caeyers 2014). We cannot reject the hypothesis of zero correlation in all cases.

Too-many-to-fail: a theoretical approach

Editor’s note: This post is part of a series showcasing Barcelona GSE master projects by students in the Class of 2014. The project is a required component of every master program.


Too-many-to-fail: a theoretical approach

Author:

Jaume Martí

Master Program:

Finance

Paper Abstract:

The recent financial crisis has generated enormous economic and human costs. New regulatory framework has been proposed in order to provide banks with better incentives.

My goal in this project is to theoretically explain several market failures that happened prior to the financial crisis and propose a model that captures these phenomena in the banking sector. To end up, I suggest different macroprudential measures that could be undertaken with the ultimate objective of providing a more stable financial system.

Collusion in auctions and the role of communication to sustain it: a microeconomic approach

Editor’s note: This post is part of a series showcasing Barcelona GSE master projects by students in the Class of 2014. The project is a required component of every master program.


Collusion in auctions and the role of communication to sustain it: a microeconomic approach

Author:

Giuseppe Leonello

Master Program:

Competition and Market Regulation

Paper Abstract:

Collusion among bidders in auctions is an important topic in competition economics since it decreases the seller’s revenues and the social welfare. In this project the focus will be on the role of communication among bidders for the incentives to collude.

In the literature, communication among bidders has always been treated as an exogenous variable. This assumption will be relaxed and the choice of communicate will be endogenous and function of the expected collusive profits and the expected costs of collusion represented by the risk to be catch and punished.

The auctioneer can monitor the market and the auction process to discover the collusive agreement, exerting a costly effort.

The model will find the minimum level of effort needed to make bidders not having incentives to communicate and collude. However, the auctioneer will exert this level of effort only when the expected gains are higher than expected costs. For this reason, in some case the optimal choice for the auctioneer will be to lead bidders to collude even if this will not maximize the social welfare.

Government interventions to reach the not collusive equilibrium will be discussed. In particular, they will take the form of an increase in the punishment when bidders are discovered to collude and the subsidization of the cost needed to exert the optimal level of effort.

Healthcare: Are we demanding bad goods?

Details is a trendy American style magazine showcasing movie stars and the latest in everything fashionable and chic. So when they name a health economist as one of the 50 most influential men under 45 it should raise a well-groomed eyebrow (or two).

Submitted by Scott Robertson, Master Program in Health Economics and Policy

Details is a trendy American style magazine showcasing movie stars and the latest in everything fashionable and chic.  So when they name a health economist as one of the 50 most influential men under 45 it should raise a well-groomed eyebrow (or two).

As if that doesn’t give him enough credibility, David Cutler is one of the most-cited minds in modern health economics with a persistent focus on driving the discussion of quality.  Modern Healthcare recently said he is one of the 30 people likely to have a significant impact on the future of healthcare.  Plus he’s a professor at MIT and was an advisor to U.S. Presidents Clinton and Obama.

In short: Cutler is a big deal.  If the UPF, and ostensibly the Barcelona GSE want to prove the profile of their economics program, attracting this star to inaugurate the academic year could be an indicator of success.  The auditorium filled to standing-room only shows the opportunity was not lost on students either.

UPF Economics Department
David Cutler delivers the UPF Economics Department opening lecture in October 2012. Photo credit: UPF

Continue reading “Healthcare: Are we demanding bad goods?”