Assessing the fidelity of delivery of an intervention to increase attendance at the English Stop Smoking Services.

Molly Sweeney-Magee,Dimitra Kale,Andrea Hamill,Simon Galton,Hazel Gilbert

doi:10.1186/s13012-016-0498-z

Abstract

BackgroundImplementation fidelity refers to the extent to which a proposed intervention is enacted as designed and is necessary to determine how much the intervention in question is the primary mechanism in any changes observed. Start2quit was a randomised controlled trial that aimed to improve attendance at the English Stop Smoking Service (SSS). The complex intervention combining computer-tailored personal risk letters and no-commitment (“taster”) sessions aimed at encouraging attendance at the SSS doubled attendance at the SSS and significantly increased abstinence rates, although attendance and abstinence varied between participating SSSs. Assessment of the fidelity of the delivery of the taster sessions to the protocol was embedded into the trial and is the focus of this study.MethodsEighteen SSSs participated in the study. Taster sessions were delivered by SSS advisors in the area. Of the 131 sessions delivered, 93 (71 %) were recorded and 41 (31.3 %) were selected for transcription and analysis. The taster session protocol contained 73 specified behaviours, which were independently classified into component behaviour change techniques (BCTs) using an established taxonomy for smoking cessation. All transcripts were coded by two authors with 25 % additionally coded by a third. The fidelity of each taster session was expressed as the percentage of overall protocol-specified behaviours that were delivered. Adherence to each BCT was measured as the number of behaviours applied by the advisors within each BCT divided by the total number classified within each.ResultsAdherence of protocol-specified behaviours was relatively high (median 71.23 %), though there was considerable variation (28.76 to 95.89 %) in individual sessions. Median fidelity to specific BCTs across sessions also varied from 50 to 100 %. Shorter sessions, sessions run jointly by two advisors, by female advisors, or by advisors aged 45 to 54 were associated with higher levels of adherence. There was no association between adherence and subsequent attendance at the SSS.ConclusionsThese results suggest that the delivery of the intervention of this study is not likely to have been impacted by issues of fidelity. As such, we can have greater confidence that variability in the main outcome is not due to variability in SSS advisor adherence to the protocol of the taster sessions.Trial registrationCurrent Controlled Trials ISRCTN76561916

Highlights

Implementation fidelity refers to the extent to which a proposed intervention is enacted as designed and is necessary to determine how much the intervention in question is the primary mechanism in any changes observed
This study aimed to answer the following research questions: (a) to what extent did advisors adhere to protocolspecified content and behaviour change techniques (BCTs), (b) were the characteristics of the advisors or of the sessions related to adherence to protocol-specified content, and (c) was adherence to protocol-specified content related to participants’ attendance at the Stop Smoking Service (SSS) or to validated 7-day abstinence
Adherence to each BCT was measured as the number of behaviours applied by the advisors within each BCT divided by the total number classified within each

Summary

Introduction

Implementation fidelity refers to the extent to which a proposed intervention is enacted as designed and is necessary to determine how much the intervention in question is the primary mechanism in any changes observed. Implementation fidelity refers to the extent to which a proposed intervention is enacted as designed [1]. Three core components of implementation fidelity have been proposed: treatment delivery, treatment receipt and treatment enactment [2]. Bellg and colleagues [4] have argued that without knowledge of fidelity, it is impossible to determine how much the intervention in question is the primary mechanism in any changes observed. Measurement of treatment receipt and enactment can provide important insight into the most efficacious elements of an intervention [6] but it is rarely carried out given the complexity of such assessments. The measurement of treatment delivery is a simpler process once there is a clear definition of the intervention and the necessary constituents [7]

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