Assessing the complexity of interventions within systematic reviews: development, content and use of a new tool (iCAT_SR)

Simon Lewin, Maggie Hendry, Jackie Chandler, Andrew D Oxman, Susan Michie, Sasha Shepperd, Barnaby Reeves, Peter Tugwell, Karin Hannes, Eva A Rehfuess, V Welch, Joanne E Mckenzie, Belinda Burford , Jennifer Petkovic, Laurie Anderson, Janet Harris, Jane Noyes

Research output: Contribution to journalArticle (Academic Journal)peer-review

42 Citations (Scopus)
425 Downloads (Pure)

Abstract

Background

Health interventions fall along a spectrum from simple to more complex. There is wide interest in methods for reviewing ‘complex interventions’, but few transparent approaches for assessing intervention complexity in systematic reviews. Such assessments may assist review authors in, for example, systematically describing interventions and developing logic models. This paper describes the development and application of the intervention Complexity Assessment Tool for Systematic Reviews (iCAT_SR), a new tool to assess and categorise levels of intervention complexity in systematic reviews.

Methods

We developed the iCAT_SR by adapting and extending an existing complexity assessment tool for randomized trials. We undertook this adaptation using a consensus approach in which possible complexity dimensions were circulated for feedback to a panel of methodologists with expertise in complex interventions and systematic reviews. Based on these inputs, we developed a draft version of the tool. We then invited a second round of feedback from the panel and a wider group of systematic reviewers. This informed further refinement of the tool.

Results

The tool comprises ten dimensions: (1) the number of active components in the intervention; (2) the number of behaviours of recipients to which the intervention is directed; (3) the range and number of organizational levels targeted by the intervention; (4) the degree of tailoring intended or flexibility permitted across sites or individuals in applying or implementing the intervention; (5) the level of skill required by those delivering the intervention; (6) the level of skill required by those receiving the intervention; (7) the degree of interaction between intervention components; (8) the degree to which the effects of the intervention are context dependent; (9) the degree to which the effects of the interventions are changed by recipient or provider factors; (10) and the nature of the causal pathway between intervention and outcome. Dimensions 1–6 are considered ‘core’ dimensions. Dimensions 7–10 are optional and may not be useful for all interventions.

Conclusions

The iCAT_SR tool facilitates more in-depth, systematic assessment of the complexity of interventions in systematic reviews and can assist in undertaking
Original languageEnglish
Article number76
Number of pages13
JournalBMC Medical Research Methodology
Volume17
DOIs
Publication statusPublished - 26 Apr 2017

Structured keywords

  • BTC (Bristol Trials Centre)
  • Centre for Surgical Research

Keywords

  • Complex interventions
  • systematic review
  • tool
  • intervention development
  • evidence synthesis
  • complex
  • intervention
  • complexity

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