pyramid levels

Question 1

case reports

Answer 1

lowest level
first line of evidence, new diseases etc.

Question 2

case control study

Answer 2

2nd lowest level
multiple risk factors seen, establish association, faster studies.
retrospective

Question 3

cohort study

Answer 3

3rd lowest level
cohorts studied to determine risk factors for a disease by following after exposure
possible to standardize results
not able to randomize, blinding difficult

Question 4

randomized control trial

Answer 4

middle level
random assignment into control or case group
easy to blind but expensive
volunteer bias risk

Question 5

practice guidelines

Answer 5

3rd highest level
produced by panel of experts
outlines best practices

Question 6

systematic review

Answer 6

2nd highest level
comprehensive review of all relevant studies on a topic, published or unpublished
results can be generalized and extrapolated
evidence based source

Question 7

meta-analysis

Answer 7

highest level
like systematic review but establishes statistical sugnificance