This document discusses critical appraisal of research evidence and provides resources for appraising different types of studies. It introduces the Critical Appraisal Skills Programme (CASP), which provides checklists for appraising systematic reviews and other study designs. The CASP checklist for systematic reviews is described in detail, including the screening questions to determine if a full appraisal is warranted, and the three main sections that assess validity of results, describe the results, and determine local applicability. Resources like CASP are important for evidence-based practitioners to evaluate the quality and applicability of scientific literature.
Critical appraisal of research evidence: The CASP resources
1. Capacity building in Policy Briefs’ Development Workshop
Critical Appraisal of
Research Evidence
DR. YASSER S. AMER
RESEARCH CHAIR FOR EVIDENCE-BASED HEALTHCARE & KNOWLEDGE TRANSLATION
CLINICAL PRACTICE GUIDELINES UNIT, QUALITY MANAGEMENT DEPT.
5. The Five Steps of EBP
Step 1: Formulating a well-built question
Step 2: Searching and screening E
Step 3: Critical Appraisal of E
Step 4: Implementing the E – change clinical or
public health practice!
Step 5: Re-evaluation
7. Critical appraisal (CA)
How do we know which evidence is sound?
How do we handle the volume of evidence?
The danger of accepting “the voice of
authority” accepting face value of research
8. Outline
•Resources for critical appraisal of the
literature.
•The Critical Appraisal Skills Programme
(CASP).
•Highlight the CASP checklist for SR
10. Methods of CA: Informal
1. Need to know something about the study type.
2. Need to know how to assess the quality of the
study type.
3. Read through the publication and make notes on
the good and bad points.
4. Reach an overall conclusion.
11. Methods of CA: Formal
CA easily using various structured checklists
http://www.equator-network.org/
16. Cochrane Handbook
Chapter 8: Assessing risk of bias in
included studies
Chapters 11 and 12: GRADE and
Summary of Findings Tables
17. Tools for CA of Quality & RoB in SRs
1. A MeaSurement Tool to Assess systematic Reviews
(AMSTAR)
2. AMSTAR 2
3. Risk Of Bias In Systematic reviews (ROBIS)
19. Resources for critical appraisal of research
(Checklists) : CASP
https://casp-uk.net/casp-tools-checklists/
20. • Useful source of checklists that cover many study designs.
• The Critical Appraisal Skills Programme (CASP) is part of
the Oxford Centre for Triple Value Healthcare Ltd; a public
health resource Unit to support change within UK NHS to
improve health and healthcare & achieve optimal
outcomes for individuals and populations. https://casp-uk.net/
21. CASP Appraisal Checklists
CASP checklists are more simple than specific CA checklists.
These checklists were designed to be used as educational
pedagogic tools, as part of a workshop setting, therefore we
do not suggest a scoring system.
The core CASP checklists (RCT& SR) were based on JAMA
'Users’ guides to the medical literature 1994 (adapted from
Guyatt, Sackett, and Cook), and piloted with HCPs.
Produced specifically for practitioners rather than more
academic interests.
23. Process of CA using CASP tools
1.Start with a general read of the paper.
2.Identify the study design the paper describes.
3.Choose the appropriate CASP tool to the study
design.
4.Work throughout the paper answering the
selected CASP tool’s questions
24. Narrative reviews cannot be critically
appraised as they have no methods section.
Reviews are only as good as the studies upon
which they are based (i.e. biases in the 1ry
studies cannot be fixed by doing a systematic
review).
25. How to use CASP checklist for SR
10 questions
Three board issues to be considered:-
1. Are the study results valid (Section A)
2. What are the results (Section B)
3. Will the results help locally (Section C)
By using the checklist you will systematically address these
issues.
26. Why Systematic Reviews?
Systematic reviews are summaries of research evidence that address a clearly
formulated question using systematic and explicit methods to :-
◦ identify, select, and critically appraise relevant research
◦ collect and analyse data from the studies that are included in the review
Systematic reviews of research evidence constitute a more appropriate source of
research evidence for decision-making than the latest or most heavily publicized
research study.
27. Advantages of Systematic Reviews
Reduce the RoB in selecting and interpreting the results of studies.
Reduce the risk of being misled by the play of chance in identifying
studies for inclusion, or the risk of focusing on a limited subset of
relevant evidence.
Provide a CA of the available research and place individual studies
or subgroups of studies in the context of all of the relevant evidence.
Allow others to appraise critically the judgements made in selecting
studies and the collection, analysis and interpretation of the results.
28. Using the CASP appraisal checklist-
Screening questions
The first two questions are screening
questions.
They will help you decide if it is worth
continuing to read the paper.
29. Screening questions for SRs
The first two questions are screening questions and can be
answered quickly.
If the answer to both is “YES”, it is worth proceeding with the
remaining questions.
There is some degree of overlap between the questions, you
are asked to record a “yes”, “no” or “can’t tell” to most of the
questions.
A number of italicized prompts are given after each question. These are
designed to remind you why the question is important.
41. Summary
Critical appraisal is an important part of EBHC,
EBPH, and EBHPM.
Healthcare providers, public health practitioners,
and policy makers throughout their careers are
required to carry out informal and formal appraisal of
scientific literature.