Basic research module I - critical appraisal

1. Critical appraisal
Research module – Basic research I
Dr Tan Chai Eng
Dept of Family Medicine
UKM

2. What is critical appraisal?
• “The process of carefully and systematically
examining research to judge its
trustworthiness and its value and relevance in
a particular context” (Burls 2009)

3. Why is critical appraisal important?
• To ensure that what is presented by the
authors are valid
• To determine whether the study results are
applicable to your population
• To ensure you are practising evidence-based
medicine in your clinical practice.

4. Controversies in medical research
• Research findings need to be evaluated
carefully to avoid making inaccurate
conclusions!
http://i.dailymail.co.uk/i/pix/2012/01/17/article-2087649-0F7E35C600000578-
697_468x242.jpg
Wakefield, 1998. Lancet
Autism and MMR
HRT and breast cancer

5. Common misconception about
research articles
• It was published in a scientific journal so it
must be correct...right? (MYTH)
TRUTH
• It should have undergone peer review but needs
to be appraised to avoid misinterpreting the
results
• Some journals get payment from authors to
publish, irregardless of quality of research

6. Oh, rats! I should have paid
attention in biostatistics and
epidemiology class!

7. Critical appraisal – How to do it?
Research question
Literature search (PICO)
Select titles relevant to your study
Read the abstract to get a rough idea about
the study setting, methodology and findings
It doesn’t stop
here!!!

8. Critical appraisal - How to do it?
Obtain the full-text of the research
article
Read the whole article!
•Introduction – background and objectives of study
•Methodology – study population, setting, study design, data
collection
•Results – analysis, any confounding factors
•Discussion – compare and contrast findings, supported by
literature
•References – reliable references? Any potential articles to be
snowballed?

9. • Does it relate to the topic you are searching
for? Does it contain the important keywords?
• Does it mention where the study was done?
• Does it mention what type of study design
was used?
• Does it mention what outcome it has studied?
1: Title of the paper

10. 2: Author of the paper
• Who are the authors?
• What are the affiliations of these authors? –
relevant expertise, location of institution
• Who is the corresponding author? -
important to obtain permissions etc.

11. 3: Abstract
• Can be structured or unstructured, depending
on requirements of journal.
• Should have:
• Brief introduction of research problem / question and
study objectives
• Summary of methodology
• Summary of results
• Discussion or conclusion
• Length of abstract depends on journal
requirements.

12. 4: Introduction
• Should provide a background of why the study
was conducted, relevant literature regarding
the topic.
• Final paragraph usually states the objective /
aim of the study.
• May content several key references that you
should search for and read as well!

13. 5: Methodology
• Study population: where and what type of
population? E.g. community setting, primary
care setting, specialist setting? Specific
disease conditions? Asian or Western?
• The above will affect whether the findings can
be comparable with your own results.
• If no local studies, or regional studies, then
international studies / foreign studies are
useful.

14. 5: Methodology
• Study design
– Cross-sectional?
– Prospective / retrospective cohort?
– Case-control (retrospective)?
– Clinical trial?
– Systematic review?
– Qualitative?
• Different study designs will have different
checklists for rigor (quality) of methodology

15. Critical appraisal checklist for various
study designs
• Critical appraisal skills programme, UK:
http://www.casp-uk.net/#!casp-tools-
checklists/c18f8
• Qualitative research :
http://intqhc.oxfordjournals.org/content/intq
hc/19/6/349.full.pdf

16. 6: Results
• Presentation of data in tables, charts that are
easy to understand.
• Statistical significance? p value < 0.05?
• Strength of correlation? r (correlation
coefficient) value?
• Prediction? Adjusted OR?

17. 7: Discussion
• Comparing (same findings) and contrasting
(different findings) results with other studies
• Reasonable and logical explanation for the
differences if any
• What are the strengths and limitations of the
study? Are there other strengths and
limitations not declared by the authors?

18. 8: Conclusion
• Is the conclusion from the study valid
(appropriate methodology, valid tools, correct
analysis)?
• Is the conclusion based on the findings of the
study?
• Is the findings of the study relevant to your
research topic? Can it be applied for your
research proposal?

19. Finally…
• What have I learnt from reading this paper?
• What are the things that can be improved
from this study? Can I overcome the
limitations and improve it in my research?
• Enter the relevant information into your
literature review table.
• Skills from critical appraisal can help you in
preparing your proposal as well as in writing
up your research dissertation.

20. To ensure comprehension…
• Try to appraise the papers in the assignments
section.
• Any queries can be discussed in the discussion
section.