A case study of a theory-based method for identifying and reporting core functions and forms of evidence-based interventions

Abstract

Adaptation of existing evidence-based interventions (EBIs) to improve their fit in new contexts is common. A critical first step in adaptation is to identify core functions (purposes) and forms (activities) of EBIs. Core functions should not be adapted as they are what account for the efficacy of EBIs. Despite their importance, core functions are rarely identified by EBI developers; methods for identifying them post hoc are lacking. We present a case study of theory-based methods for identifying core functions and forms post hoc. We developed these methods as the first step in a larger effort to adapt an existing EBI to improve the timeliness of referrals to hospice to a new patient population and care setting. Our methods were rooted in the Planned Adaptation Model (PAM). Through our case study, we developed six steps for identifying core functions and forms, as well as accompanying tools and methods. Our case study further operationalized PAM in several ways. Where PAM offered guiding tenets for identifying core functions and forms (review existing EBI materials, conduct primary data collection, and identify the theory of change), we produced specific tools (interview guides and codebooks) and methods (sampling approaches and analytic methods). Our case study extended PAM with the addition of two steps in the process of identifying core functions and forms: (a) identifying the usual care pathway, including barriers to the outcome of interest encountered in usual care, and (b) mapping EBI core functions onto an extant theory. Identifying core functions and forms is a critical first step in the adaptation process to ensure adaptations do not inadvertently compromise the efficacy or effectiveness of the EBI by compromising core functions. Our case study presents step-by-step methods that could be used by researchers or practitioners to identify core functions and forms post hoc.

Focusing on fidelity: narrative review and recommendations for improving intervention fidelity within trials of health behaviour change interventions

“…To date, evidence is inconclusive regarding whether adaptations have a positive, negative or neutral effect on intervention outcomes (Breitenstein et al, 2010 ). With this in mind, more recently, it is suggested that achieving an appropriate balance between fidelity and adaptation is needed and that in certain circumstances adaptation may in fact be a critical element of a behaviour change intervention (Hawe, Shiell, & Riley, 2004 ; Holliday et al, 2009 ; Kirk et al, 2019 ; McHugh et al, 2009 ). However, despite the clear need for careful and explicit consideration of intervention adaptation and what is considered ‘appropriate’ or desirable, several systematic reviews have shown that this particular aspect remains an under-addressed area of health behaviour change intervention research (Durlak & DuPre, 2008 ; Yamato, Maher, Saragiotto, Hoffmann, & Moseley, 2016 ; Yu, Balasubramanaiam, Offringa, & Kelly, 2018 ).…”

“…a video or booklet), or the operationalisation of a behaviour change technique (BCT) to be adapted, as long as it retains fidelity to the underlying intervention theory (Keogh, Matthews, & Hurley, 2018 ) or the ‘function’ of the component or BCT (e.g. to ‘provide instruction on how to perform the behaviour’) (Hawe, Shiell, & Riley, 2004 ; Hawe, Shiell, Riley, & Gold, 2004 ; Kirk et al, 2019 ; McHugh et al, 2009 ). Clear specification of the intervention components and hypothesised mechanisms of change using logic models and taxonomies such as the BCT Taxonomy v1 (Michie et al, 2013 ) is therefore essential to facilitate this.…”

Context counts: a qualitative study exploring the interplay between context and implementation success

“…Historically, deviation from the research protocol was perceived as a threat to implementation fidelity, compromising the effectiveness of the intervention (Bopp et al, 2013;Chambers and Norton, 2016). However, recent literature recognises that although the underlying principles that make the intervention effective require perfect fidelity (core functions), the tailoring of strategies which support each intervention principle (forms) is necessary to improve context fit (Kirk et al, 2019;Perez Jolles et al, 2019). Although identifying these core functions and forms strengthen local implementation, these components are rarely specified by intervention developers (Kirk et al, 2019).…”

Implementation of Complex Interventions

“…Core functions and forms can also be identified post hoc. 28 The idea of making causal pathways explicit is also reflected in PCORI’s methodology standards for studies of complex interventions. 22 In the case studies below, we discuss the importance of delineating function versus form.…”