1 Critical Appraisal of research evidence

Question 1

Define ‘critical appraisal’.

Answer 1

=process of carefully and systematically examining research to judge its trustworthiness, and its value and relevance in a particular context.

Question 2

What is the PICO framework used for? What does it stand for?

Answer 2

Should be able to get PICO form abstract of paper

Used to develop question you want to answer in a paper

Question 3

Give some examples of why studies get rejected. (there are lots)

Answer 3

Question 4

How do we know if there is selection bias in a study? (ie what questions should we ask?)

Answer 4

Is there a systematic difference between the people that have been selected and those that have not?

• • Is how the study sample was developed described?
• • Are the characteristics of the sample well described?
• • Is there any evidence that the sample is generalizable to the wider population?

Question 5

What are cross-sectional studies useful for? What are the main limitiations of a crossectional study?

Answer 5

Useful for: determining burden of disease, generating hypotheses

Limitations:

• prone to selection bias
• Can’t determine temporal sequence

Question 6

What should be done to make an ecological study as reliable as possible?

Answer 6

• Population clearly defined
• Information sources- well described, reliable, accurate, complete

Question 7

What are the key issues with ecological studies?

Answer 7

Confounding= particular issue

Ecological fallacy- can make interpretation difficult

(Ecological fallacy= failure in reasoning that arises when an inference is made about an individual based on aggregate data for a group)