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Critical Appraisal. Library and Information Service Southmead Ext 5333 Frenchay Ext 6570. What is critical appraisal?. …. process of weighing up evidence to see how useful it is in decision making. Why critically appraise?. Supports sound decision making based on best available evidence
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Critical Appraisal Library and Information Service Southmead Ext 5333 Frenchay Ext 6570
What is critical appraisal? • …. process of weighing up evidence to see how useful it is in decision making
Why critically appraise? • Supports sound decision making based on best available evidence • Helps us determine: • How rigorous a piece of research is • What the results are telling us • How relevant it is to our patient
How to critically appraise? • Many different tools • http://www.cebm.net • http://www.phru.nhs.uk/casp/apprais.htm • http://www.shef.ac.uk/scharr/ir/netting But what are the three main things we are looking for?
Three R’s • Rigour - how good is the study • Results - what is it actually telling us • Relevance – is it relevant to our patient
Levels of Evidence • 1a A systematic review of 2 or more randomised control trials (RCTs) • 1b an RCT • 2a a cohort study • 2b a case control study • 2c a dramatic uncontrolled experiment • 3 Respected authorities, opinions etc • 4 …someone once told me
Sources of Evidence • Primary sources • Based on experiments and published research • Secondary sources • Systematic reviews • Clinical guidelines • Journals of secondary publication e.g. Evidence Based Medicine
Getting Started • Formulate PICO question • Search appropriate sources • Obtain article (s) • Read to suit you!
Statistics • If in doubt ask a statistician • Key points to look for • 95% confidence limits used • If p <0.05 then result is statistically significant • Any anomalies discussed • All subjects accounted for even if dropped out
Reading for Critical Appraisal • Introduction • Logical and knowledgeable • Aim/research question • Clearly stated • Methods • Fully described • Analysis • Appropriate statistics used, all subjects accounted for
Conclusions • Justified and valid • Cost/benefits discussed Can I make a clinical decision based on what I have just read?
Practical Exercise Appraise the paper given to you and be prepared to share your comments with the group
Appraising Web Sites • Authority • Currency • No advertisement/sponsorship • .org, .ac, .gov better than .co.uk/.com
Practical Exercise In groups comment on the webpages given and be ready to feedback