The Luxembourg Institute of Socio-Economic Research (LISER) has contributed to research on the effects of COVID-19 lockdown policies in 135 countries. 

Two researchers (Dr. Konstantinos Tatsiramos and Dr. Bertrand Verheyden) from LISER, together with a researcher from the Institute of Labor Economics (IZA), recently published an article evaluating the effects of lockdown policies over 135 countries on the daily incidence of COVID-19, as well as on various population mobility patterns. 

In light of the coronavirus outbreak, several countries implemented a number of lockdown measures aimed at saving human lives and prevent healthcare systems from being overwhelmed. The article by LISER and the IZA look at which policies have proven thus far to be the most effective in containing the virus and the channels through which these effects operate.

In "Lockdown strategies, mobility patterns and COVID-19", published in the Centre for Economic Policy Research's (CEPR) Covid Economics journal, the authors consider eight interventions, which vary in their timing and intensity. The policies in focus are international travel checks, public transport closures, cancellation of public events, restrictions on private gatherings, school and workplace closures, stay-at-home requirements and internal mobility restrictions. The authors’ approach, which is based on a multiple-event framework, provides an evaluation of the dynamic effects of these eight policies. By exploiting the variation in the intensity and timing of policies across countries, they are able to estimate the net effect of each policy, while taking into account the presence of concurrent policies.

The main result of the analysis is that cancelling public events, imposing restrictions on private gatherings and closing schools have the quantitatively most pronounced effects in reducing the incidence of COVID-19. These are followed by workplace closure and stay-at-home requirements, whose effects are not as prominent. On the other hand, no effects were found for international travel controls, public transport closures or restrictions on movements across cities and regions. The researchers noted that estimating the effect of each policy while ignoring the contemporaneous influence of other policies would have led to the erroneous conclusion that they are all effective in reducing new infections. 

The second part of the analysis links lockdown policies to mobility patterns in order to shed light on the mechanisms through which they help flatten the curve. Lockdown policies tend to decrease the amount of time spent outside home, which leads to a reduction in the number of infections through various channels. For instance, cancelling public events, and to a lesser extent restricting private gatherings, reduce exposure to numerous and dense locations where contact tracing is difficult. Such events, which have a large epidemiological range within and across countries, are thus the most important to restrict, according to the authors. Workplace closures have had less of an impact on lowering new infections, likely because of the lower number of people, density, and traceability in these environments. The article argues that the fact that travel controls had no impact on the evolution of the virus, although imposed relatively early in many countries, is likely explained by their lack of stringency, which allowed the virus to exploit the smallest breach and spread across borders, rendering them immaterial for the ensuing domestic epidemics.