Reliability and validity of the German “Evidence-Based Practice Confidence (EPIC) Scale” for allied health professionals

Introduction

The Evidence-Based Practice Confidence (EPIC) Scale measures health professionals’ self-efficacy associated with evidence-based practice activities. The scale has been cross-culturally translated into German together with physical therapists. To support its use in German-speaking countries, the measurement properties of the scale need to be determined. Therefore, the primary objective of this study was to assess the measurement properties of the German EPIC scale. In a preparatory step, we aimed to evaluate the comprehensibility of the scale among German-speaking occupational therapists, speech and language therapists, and nurses.

Methods

First, semi-structured cognitive interviews were used to evaluate the comprehensibility of the EPIC scale. Second, a longitudinal online survey with repeated measures (baseline and retest survey) was conducted. The target group included physical therapists, occupational therapists, speech and language therapists, and nurses from Germany, Austria, and Switzerland. Reliability, responsiveness, and validity were evaluated using internal consistency, test-retest reliability, standard error of measurement, known-groups method, exploratory factor analysis and the minimal detectable change, respectively.

Results

Comprehensibility of the German EPIC scale was confirmed by eleven health care professionals (four occupational therapists, two speech and language therapists, five nurses). The baseline and the retest surveys were completed by 708 and 222 participants, respectively. The measure demonstrated an internal consistency of .930, with an intraclass correlation coefficient (ICC) for test-retest reliability of .936 (95% CI: .917 to .951). The standard error of measurement was 4.92, and the minimal detectable change at the 95% confidence level was 6.02. All hypotheses in the known-groups method were confirmed, and construct validity was acceptable. Factor analysis revealed two main factors affecting the results of the scale.

Conclusion

The findings provide evidence that supports the use of the German EPIC scale among health professionals. For instance, it can be used to evaluate self-efficacy during EBP training.