Could a planned cyclic lifting of lockdown help us safely re-open the economy?

Researchers from the University of Oxford have suggested that a cyclical policy, in which restrictions are removed from and then again imposed on different population groups, could help to end the current lockdown. The process would also act as a randomized controlled trial to test the effectiveness of social distancing policies in fighting the Covid-19 pandemic.

The researchers—Professor Philip Clarke and senior researcher Laurence Roope, both of the University of Oxford—suggest the population could be split by odd and even house numbers. People living in odd-numbered properties would have their lockdown restrictions eased one week, with even-numbered properties eased the next week. They would thus cycle in and out of lockdown, the idea being that only half the usual population numbers would be outside at any one time, reducing the risk of virus transmission.

Several governments around the world have already trialled cyclical policies, including for example Colombia, where men and women were allowed out on odd and even days of the month, and Honduras, where the public were allowed to conduct essential travel one day each week, with the day determined by the last digit on their ID documents.

One of the major advantages of such a policy is that it would allow a greater and more predictable level of economic activity to continue—for instance, pubs and cafes could reopen, but with half the customers. It could also assist the development of the current test-and-trace system as there would be fewer cases and as a result fewer contacts to trace.

In her IZA World of Labor article, Zahra Siddique notes that randomized controlled trials are frequently characterized by imperfect compliance “when not all subjects who have been randomly selected to take a treatment actually choose to do so, or when those randomly assigned not to take the program decide instead to take it.” So, in this case, if the odd- and even-numbered populations go out on the days they should stay in or stay in on the days they are allowed to go out. Siddique notes however that “useful information on treatment effectiveness can still be recovered by estimating ‘bounds,’ or a range of values in which treatment effectiveness can lie.”

Clarke and Roope say the cyclical approach to lockdown would provide the government with robust experimental evidence which would enable them to find the best ways to combat Covid-19 and save lives.