Assessing healthcare interventions along the complex-simple continuum: a proposal

Tags: Poster
Lewin S, Oxman A, Glenton C

Background: Healthcare interventions fall along a spectrum from simple to highly complex. There is growing interest in the design and evaluation of so-called complex interventions, but little work has been conducted on how intervention complexity might be conceptualised or assessed.

Objectives: To conceptualise, design and validate a tool for grading healthcare interventions along the complex-simple continuum.

Methods: The tool was developed through review of the literature and a series of discussions with trialists, intervention developers and other scientists. The draft tool was then applied to published reports of trial interventions and revised. Inter-rater agreement in application of the tool was assessed and guidelines for its use developed.

Results: Six key dimensions of intervention complexity were identified: (1) the number of discrete, active components included in the intervention(s) compared with the control; (2) the number of behaviours or actions of intervention recipients to which the intervention is directed; (3) the number of organisational levels targeted by the intervention; (4) the degree of flexibility permitted across sites or individuals in intervention implementation; (5) the level of skill required by those delivering the intervention; (6) and the level of skill required for the targeted behaviour when entering the study by those receiving the intervention. For each dimension, interventions may be rated as simple, intermediate or complex. The application of the tool to published reports of interventions, including inter-rater agreement, is discussed.

Conclusions: A tool to assess healthcare interventions along the complex-simple continuum is feasible and may be useful in developing and describing interventions; in understanding their measured effects; and in exploring the causes of heterogeneity in effect estimates within systematic reviews. The tool may also draw health planners' attention to the resources needed to implement health interventions. Further discussion and research on the application of the tool is needed.