title: Error in formula by Salbach et al.
authors.affiliation: Professor of Health Statistics, Department of Health Sciences, University of York. Martin.bland@york.ac.uk.
authors.forename: John Martin
authors.initials: JM
authors.lastname: Bland
mesh_terms: D055317:Evidence-Based Practice; D005260:Female; D006801:Humans; D008297:Male; D059825:Physical Therapists / Q000523:psychology*; D020377:Self Efficacy; D011795:Surveys and Questionnaires