Fidelity of Intervention Implementation: A Review of Instruments

Background: Interventions, whether simple or complex, are increasing in health care in response to the growing complexity and acuity of patient’s conditions. Monitoring the fidelity of implementing interventions is challenging. A common method to assess and monitor fidelity of intervention implementation is through a structured, reliable and valid instrument. Purpose: The purpose of this paper is to examine existing instruments measuring fidelity of intervention implementation in order to determine aspects of fidelity that have been assessed and reported on the reliability and validity of these instruments. Design: A descriptive review was conducted. Studies were included if they described and reported on the fidelity of intervention implementation instruments, their psychometric properties were published between 1980 and 2015. Methods: Data were extracted on the study characteristics, levels and aspects of fidelity and the psychometric properties, specifically the reliability and validity of the fidelity of intervention implementation instruments. Results: In total, 21 studies were included in the review. Overall results showed that some aspects and levels of fidelity of intervention implementation are included in the instruments. At the theoretical level, fidelity of intervention implementation is not accounted for majority of the studies and few explicitly reports on the use of instruments to evaluate intervention differentiation. At the operational level, interventionists’ adherence and competence are included in the instruments; however, participants’ engagement, exposure and enactment are not. The instruments demonstrate acceptable level of validity and reliability. Conclusion: Sustained focus on developing psychometrically sound instruments that account for all levels (i.e. theoretical and operational) and aspects of fidelity of intervention implementation is imperative to strengthen the methodological literature for interventions research; and for researchers to correctly interpret research findings and to arrive at valid conclusions on the effectiveness of interventions, whether simple or complex.