Focus the question so that it is answerable, determines the objective of the literature search, and informs the tools used for appraisal. Questions can generally be structured in terms of a relationship among the patient (P), an intervention (I), sometimes a comparison intervention (C), and one or more specific outcomes of interest (O).
Flemming K. Asking answerable questions [editorial].Evidence-Based Nursing 1998 Apr;1:36-7.
Richardson W, et al. The well-built clinical question: a key to evidence-based decisions.
ACP Journal Club 1995 Nov- Dec;123(3):A12-3.
Shaneyfelt, T. (2012, September 30). Developing answerable clinical questions [Video File]. Retrieved from https://www.youtube.com/watch?v=CK5ppoS4Pf8
Acquiring information / ANA Nursing World
Databases and resources / ANA Toolkit
Tutorials on database searching / PubMed Basics / ANA
Appraising the evidence / Sage Publications
Critical Appraisals for Summaries of Evidence (CASE) / JMLA
CASE Worksheet / JMLA (revised worksheet)
Critical Appraisal of Evidence / KT Clearinghouse
Evidence-based Medicine Toolbox / Knowledge Translation
Critical appraisal worksheets / (Centre for Evidence-Based Medicine)
Critical appraisal worksheets / (Duke Univ.)
Essentials of nursing research [electronic resource] : appraising evidence for nursing practice / Denise F. Polit, Cheryl Tatano Beck
Polit, Denise F.
Critical appriasal of RCTs--quick tips 
A Model for Applying Evidence to Nursing Practice / by Jeanne Grace, RN, PhD1
J Nurs Sci Vol 30 No 2 April - June 2012
Implementing Evidence-based nursing: some misconceptions (BMJ)