UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

Optimal design of cluster randomised trials with continuous recruitment and prospective baseline period

Hooper, R; Copas, AJ; (2021) Optimal design of cluster randomised trials with continuous recruitment and prospective baseline period. Clinical Trials , 18 (2) pp. 147-157. 10.1177/1740774520976564. Green open access

[thumbnail of Hooper_Optimal design of cluster randomised trials with continuous recruitment and prospective baseline period_VoR.pdf]
Preview
Text
Hooper_Optimal design of cluster randomised trials with continuous recruitment and prospective baseline period_VoR.pdf

Download (1MB) | Preview

Abstract

BACKGROUND: Cluster randomised trials, like individually randomised trials, may benefit from a baseline period of data collection. We consider trials in which clusters prospectively recruit or identify participants as a continuous process over a given calendar period, and ask whether and for how long investigators should collect baseline data as part of the trial, in order to maximise precision. METHODS: We show how to calculate and plot the variance of the treatment effect estimator for different lengths of baseline period in a range of scenarios, and offer general advice. RESULTS: In some circumstances it is optimal not to include a baseline, while in others there is an optimal duration for the baseline. All other things being equal, the circumstances where it is preferable not to include a baseline period are those with a smaller recruitment rate, smaller intracluster correlation, greater decay in the intracluster correlation over time, or wider transition period between recruitment under control and intervention conditions. CONCLUSION: The variance of the treatment effect estimator can be calculated numerically, and plotted against the duration of baseline to inform design. It would be of interest to extend these investigations to cluster randomised trial designs with more than two randomised sequences of control and intervention condition, including stepped wedge designs.

Type: Article
Title: Optimal design of cluster randomised trials with continuous recruitment and prospective baseline period
Location: England
Open access status: An open access version is available from UCL Discovery
DOI: 10.1177/1740774520976564
Publisher version: https://doi.org/10.1177%2F1740774520976564
Language: English
Additional information: © 2021 by The Society for Clinical Trials. This article is distributed under the terms of the Creative Commons Attribution 4.0 License (https://creativecommons.org/licenses/by/4.0/).
Keywords: Efficient design, group randomised trials, power, sample size
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute for Global Health
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute for Global Health > Infection and Population Health
URI: https://discovery.ucl.ac.uk/id/eprint/10123635
Downloads since deposit
64Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item