Sam Watson’s journal round-up for 7th November 2016

Every Monday our authors provide a round-up of some of the most recently published peer reviewed articles from the field. We don’t cover everything, or even what’s most important – just a few papers that have interested the author. Visit our Resources page for links to more journals or follow the HealthEconBot. If you’d like to write one of our weekly journal round-ups, get in touch.

The view from above: applications of satellite data in economics. Journal of Economic Perspectives [RePEc] Published October 2016

Images of the earth from above have been used for economic analysis for the better part of a century. Photographs taken from aeroplanes were used to map agricultural land use in the US in the 1930s and 1940s, for example. Since that time the remotely sensed data available to economists have grown exponentially as modern satellites provide very high resolution imagery across a wide range of spectral bands. This discussion article summarises the methods and use of these new data, which have already shown to be useful for those working in health. We recently discussed the issue of measuring neighbourhood effects in slums, one recent paper used satellite imagery of Kibera, Nairobi to identify dwellings that had replaced their roofs. Such information could be linked to other data sources such as the Demographic and Health Surveys, as another recent paper has done. Another health-related example provided in this article is a paper that used satellite data to map air pollution from forest fires, which are then used to estimate excess infant deaths in Indonesia. Satellite data can provide an important source of information for areas where few other data are available, they have high spatial resolution, and have a wide geographic coverage, making them a potential boon for health research. Nevertheless, the use of these data is still in its early days, and the best statistical methods, particularly for causal inference, are still to be settled upon.

Arrival by ambulance explains variation in mortality by time of admission: retrospective study of admissions to hospital following emergency department attendance in England. BMJ Quality and Safety [PubMedPublished October 2016

The UK government’s plans to increase provision of health care services at the weekend – the seven day NHS policy – has generated large controversies. The policy has been justified on the basis of the so-called ‘weekend effect’, that patients who are admitted to hospital at the weekend are more likely to die than their counterparts admitted on a weekday. This evidence has been widely questioned, as we have discussed here, here, and here. Part of the problem is that patients who are admitted at the weekend differ from those admitted on a weekday in that they are more likely to be in worse health. So far, there has been little success in the development of adequate and convincing risk adjustment schemes using routine data. This article attempts to address this issue by using mode of arrival at the accident and emergency department to control for severity of illness. The authors report that under a standard risk adjustment model, there appears to be some evidence of an increased risk of mortality among weekend and weeknight admissions relative to Wednesday daytime admissions (odds ratio approximately 1.07), which is slightly lower than the risks reported elsewhere. However, after adjusting for mode of arrival, nights no longer appear worse, and only Sunday daytime admissions show evidence of an increased risk of mortality relative to Wednesday daytime admissions. Mode of arrival is a relatively blunt measure of severity of illness as you either do not arrive by ambulance or you do. But, an important tenet of any statistical analysis is to examine the robustness of the results to changes in model specification, and this article demonstrates that controlling for mode of arrival affects the results and hence conclusions that can be made from this study. This article adds to the growing evidence base that the evidence surrounding the ‘weekend effect’ is not as clear-cut as some would have you believe.

Worms at work: long-run impacts of a child health investment. The Quarterly Journal of Economics [RePEcPublished October 2016

The treatment of worms (helminths) is cheap, but diagnosis is expensive, so periodic mass de-worming programmes have been recommended by the World Health Organization in high-risk areas. However, a recent Cochrane review concluded that there was strong evidence that such programmes do not improve nutrition, health, or schooling outcomes. But, as this paper notes, the Cochrane review excluded a number of rigorous non-individual randomised studies, such as the analysis of a school based trial in Kenya, which showed large increases in school participation. This article presents a ten year follow up of this Kenyan trial. The authors report that they find increases in the proportion of people reporting their health as ‘very good’ and an increase in the number of hours in the labour market provided by males. But, the effects are small. Nevertheless, the potential government revenues from the increased labour market activity are potentially greater than the direct subsidy cost of the deworming programme, suggesting that it is potentially Pareto improving. Taken in light of the evidence in the Cochrane review, though, I do not remain fully convinced of the benefits of the deworming programme.

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