Statistical analysis plan for a cluster randomised controlled trial to compare screening, feedback and intervention for child anxiety problems to usual school practice: identifying Child Anxiety Through Schools-identification to intervention (iCATS-i2i)


Background: The Identifying Child Anxiety Through Schools-identification to intervention (iCATS-i2i) trial is being conducted to establish whether ‘screening and intervention’, consisting of usual school practice plus a pathway comprising screening, feedback and a brief parent-led online intervention (OSI: Online Support and Intervention for child anxiety), bring clinical and health economic benefits compared to usual school practice and assessment only — ‘usual school practice’, for children aged 8–9 years in the following: (1) the ‘target population’, who initially screen positive for anxiety problems according to a two-item parent-report child anxiety questionnaire — iCATS-2, and (2) the ‘total population’, comprising all children in participating classes. This article describes the detailed statistical analysis plan for the trial. Methods and design: iCATS-i2i is a definitive, superiority, pragmatic, school-based cluster randomised controlled trial (with internal pilot), with two parallel groups. Schools are randomised 1:1 to receive either screening and intervention or usual school practice. This article describes the following: trial objectives and outcomes; statistical analysis principles, including detailed estimand information necessary for aligning trial objectives, conduct, analyses and interpretation when there are different analysis populations and outcome measures to be considered; and planned main analyses, sensitivity and additional analyses. Trial registration: ISRCTN76119074. Registered on 4 January 2022

Publication DOI:
Divisions: College of Health & Life Sciences > School of Psychology
College of Health & Life Sciences > Aston Institute of Health & Neurodevelopment (AIHN)
College of Health & Life Sciences
Funding Information: This study is funded by the National Institute for Health and Care Research (NIHR) Programme Grants for Applied Research (Reference Number: RP-PG-0218–20010). C. C. was supported by the Oxford and Thames Valley National Institute for Health Research Appli
Additional Information: Copyright © 2024. The Author(s). This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.
Uncontrolled Keywords: Anxiety problems,Cluster randomised controlled trial,Estimand,School based,Screening,Statistical analysis plan,Humans,Parents,Anxiety/therapy,Anxiety Disorders,Feedback,Child,Schools,Pharmacology (medical),Medicine (miscellaneous)
Publication ISSN: 1745-6215
Last Modified: 17 May 2024 07:22
Date Deposited: 18 Jan 2024 10:39
Full Text Link:
Related URLs: https://trialsj ... 063-023-07898-6 (Publisher URL)
http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Article
Published Date: 2024-01-17
Accepted Date: 2023-12-19
Submitted Date: 2023-09-26
Authors: Ball, Susan
Reardon, Tessa
Creswell, Cathy
Taylor, Lucy
Brown, Paul
Ford, Tamsin
Gray, Alastair
Hill, Claire
Jasper, Bec
Larkin, Michael (ORCID Profile 0000-0003-3304-7000)
Macdonald, Ian
Morgan, Fran
Pollard, Jack
Sancho, Michelle
Sniehotta, Falko F.
Spence, Susan H.
Stainer, Jason
Stallard, Paul
Violato, Mara
Ukoumunne, Obioha C.



Version: Published Version

License: Creative Commons Attribution

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