RESUMO
OBJECTIVES: To develop and validate an instrument to measure Brazilian healthcare professionals' perceptions, behaviour, self-efficacy and attitudes towards evidence-based health practice. DESIGN: Validation of an instrument using the Delphi method to ensure content validity and data from a cross-sectional survey to evaluate psychometric characteristics (psychometric sensitivity, factorial validity and reliability). SETTING: National Register of Health Establishments database. PARTICIPANTS: We included clinical health professionals who were working in the Brazilian public health system. RESULTS: The Instrument to assess Evidence-Based Health (I-SABE) was constructed with five domains: self-efficacy; behaviour; attitude; results/benefits and knowledge/skills. Content validity was done by 10-12 experts (three rounds). We applied I-SABE to 217 health professionals. Bartlett's sphericity test and the Kaiser-Meyer-Olkin (KMO) index were adequate (χ2=1455.810, p<0.001; KMO=0.847). Considering the factorial loads of the items and the convergence between the Scree Plot and the Kaiser criterion the four domains tested in this analysis, explaining 59.2% of the total variance. The internal consistency varied between the domains: self-efficacy (α=0.76), behaviour (α=0.30), attitudes (α=0.644), results/benefits to the patient (α=0.835). CONCLUSIONS: The results of the psychometric analysis of the I-SABE confirm the good quality of this tool. The I-SABE can be used both in educational activities as well as an assessment tool among healthcare professionals in the Brazilian public health settings.