Validity and Reliability Evidence for a New Measure: The Evidence-Based Practice Knowledge Assessment in Nursing.

Abstract

Studies of evidence-based practice (EBP) among nurses often focus on attitudes and beliefs about EBP and self-reported EBP knowledge. Because knowledge self-assessments can be highly inaccurate, the authors developed and tested a new objective measure of EBP knowledge--the Evidence-Based Practice Knowledge Assessment in Nursing (EKAN). Seven subject matter experts reviewed candidate items, resulting in a scale content validity index of 0.94. Rasch modeling was used to evaluate item-person performance on the proposed unidimensional trait of EBP knowledge. The candidate item pool was then tested among 200 undergraduate nursing students. Strong evidence of unidimensionality was confirmed by narrow item infit statistics centering on 1.0. The item separation index was 7.05, and the person separation index was 1.66. Item reliability was 0.98, and person reliability was 0.66. The 20-item EKAN showed strong psychometric properties for an instrument developed under the Rasch model and is available for use in research and educational contexts.