The #effect of a #terrorist #attack on #emergency department inflow: an observation study using difference-in-differences methodology (Scand J Trauma Resusc & Emerg Med., abstract)

[Source: Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine, full page: (LINK). Abstract, edited.]

Original research / Open Access

The effect of a terrorist attack on emergency department inflow: an observation study using difference-in-differences methodology

Andreas Ekström, Fredrik Eng-Larsson, Olov Isaksson, Lisa Kurland and Martin Nordberg

Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine, 201927:57
/ DOI:

©  The Author(s). 2019

Received: 5 March 2019 – Accepted: 17 May 2019 – Published: 24 May 2019



Study objective

The objective of this study was to investigate how the terrorist attack in Stockholm, Sweden affected patient inflow to the general emergency departments (EDs) in close proximity of the attack. The study analyzed if, and to what extent, the attack impacted ED inflow during the following days and weeks.


In a retrospective observational study, anonymized aggregated data on ED arrivals (inflow of patients) to all seven of the EDs in the Stockholm County was analyzed using the Difference-in-Differences (DiD) estimator. The control groups were the affected hospitals in the years prior to the terrorist attack. The number of ED visits was retrieved from the Stockholm County Council administrative database.


The study shows a statistically significant reduction in overall ED inflow of 7–9% following the attack. The effect was strongest initially after the attack, and ED inflow regained normal levels within approximately three weeks’ time, without any significant rebound effect. The effect on ED inflow also decreased with distance from ground zero, and was not significant further away than 10 km.


The results showed that ED inflow was significantly decreased in the weeks immediately following the Stockholm terrorist attack. The reasons for this cannot be fully explained in this observational study. However, the results suggest that some patients actively choose when, where and if they should go to the ED.

Keywords: Emergency service – Hospital – Patient acceptance of health care – Terrorism – Health behavior

Keywords: Terrorism; Society; Sweden.


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Giuseppe Michieli

I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum ( in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.