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 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