The Heirachy Of Evidence

Question 1

Risk of bias?

Answer 1

Increases towards case reports and opinion papers whereas with RCT less risk

Question 2

Internal validity?

Answer 2

Extent to which observed difference between groups can be correctly attributed to exposure

Question 3

Case report benefits?

Answer 3

In depth analysis
Fast and cheap
Good learning tool
Utility in emerging epidemics and previously unrecognised syndromes

Question 4

Case report disadvantages?

Answer 4

Only descriptive
Uncontrolled
Lack of generalisability
Uncertain future outcomes
Changing features to preserve anonymity could impact on usefulness