. 2021 Sep 15;185(1):202–218. doi: 10.1111/rssa.12738
© 2021 Royal Statistical Society
This article is being made freely available through PubMed Central as part of the COVID-19 public health emergency response. It can be used for unrestricted research re-use and analysis in any form or by any means with acknowledgement of the original source, for the duration of the public health emergency.