Critical Appraisals

Question 1

To study a disease prognosis, what is the best study design?

Answer 1

Cohort study

Question 2

To study a disease aetiology, what is the best study design?

Answer 2

Cohort study

Population based cohort study

Question 3

To study a disease treatment, what is the best study design?

Answer 3

RCTs and Systematic Reviews of RCTs

Question 4

To study a disease diagnostic method, what is the best study design?

Answer 4

Cross-sectional analytic study

Question 5

What are the positives of Systematic Reviews?

Answer 5

• Find results of studies with relevant inclusion / exclusion data
• Include unpublished work
• Includes ALL evidence
• Includes non-English work
• Increases sample size
• Indicates variation between studies
• Allows sub-group analysis
• Allows sensitivity analysis

Question 6

In Medline searches, what does the asterisk (*) denote?

Answer 6

Truncation

Question 7

What is the definition of bias?

Answer 7

Systematic introduction of error which distorts results in a non-random way

Question 8

What does the phrase “Study validity” mean?

Answer 8

Believe-ability / credibility of results

Question 9

Outline the ten steps of the CASP checklist to Critically Appraise evidence

Answer 9

1. Clearly focused question?
2. Right type of study included?
3. Was all studies included?
4. Quality assessment tool?
5. If combined results, is this reasonable?
6. How are results presented?
7. Are results precise?
8. Can results apply to population?
9. Were all outcomes considered?
10. Should policy change because of this?