German language questionnaires for assessing implementation constructs and outcomes of psychosocial and health-related interventions: a systematic review

BACKGROUND: Over the past years, implementation science has gained more and more importance in German-speaking countries. Reliable and valid questionnaires are needed for evaluating the implementation of evidence-based practices. On an international level, several initiatives focused on the identification of questionnaires used in English-speaking countries but limited their search processes to mental health and public health settings. Our aim was to identify questionnaires used in German-speaking countries measuring the implementation of interventions in public health and health care settings in general and to assess their psychometric properties. METHODS: We searched five different bibliographic databases (from 1985 to August 2017) and used several other search strategies (e.g., reference lists, forward citation) to obtain our data. We assessed the instruments, which were identified in an independent dual review process, using 12 psychometric rating criteria. Finally, we mapped the instruments’ scales and subscales in regard to the constructs of the Consolidated Framework for Implementation Research (CFIR) and the Implementation Outcome Framework (IOF). RESULTS: We identified 31 unique instruments available for the assessment of implementation science constructs. Hospitals and other health care settings were the ones most often investigated (23 instruments), while education and childcare settings, workplace settings, and community settings lacked published instruments. Internal consistency, face and content validity, usability, and structural validity were the aspects most often described. However, most studies did not report on test-retest reliability, known-groups validity, predictive criterion validity, or responsiveness. Overall, the majority of studies did not reveal high-quality instruments, especially regarding the psychometric criteria internal consistency, structural validity, and criterion validity. In addition, we seldom detected instruments operationalizing the CFIR domains intervention characteristics, outer setting, and process, and the IOF constructs adoption, fidelity, penetration, and sustainability. CONCLUSIONS: Overall, a sustained and continuous effort is needed to improve the reliability and validity of existing instruments to new ones. Instruments applicable to the assessment of implementation constructs in public health and community settings are urgently needed. TRIAL REGISTRATION: The systematic review protocol was registered in PROSPERO on October 19, 2017, under the following number: CRD42017075208. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13012-018-0837-3) contains supplementary material, which is available to authorized users.