REBM

Question 1

What you call a study with this structure?

Answer 1

Case control study

Question 2

In a case control study what do you call the group of people whos outcome is the outcome in question?

Answer 2

Cases

Question 3

What is a downside to a case control study?

Answer 3

Exposure is historical hence patients often under or over estimate their exposure

Question 4

What is a case control study best used for?

Answer 4

Prognosis questions?

Question 5

What would you call a study with this structure?

Answer 5

Cohort study

Question 6

When are cohort studies useful?

Answer 6

• If there is already a strong hypothesis linking exposure to outcome
• The time between exposure and outcome is not too long
• The outcome is not too rare

Question 7

How does a randomised controlled trial differ from a cohort study?

Answer 7

They are the best when looking at the effectiveness of a specific intervention, they are also free from selection bias.

However they can be costly and have ethical issues

Question 8

What would you call a study witht his structure?

Answer 8

Cross-Sectional Study

Question 9

What are cross sectional studies useful for?

Answer 9

• Answering question of incidence or prevelence within a population
• Establishing what is the norm for specific populations at moments in time
• To justify further research on a topic, they can indicate relationships but are rarely strong evidence by themselves

Question 10

What would you can a study with this structure?

Answer 10

Case study

Question 11

What are case studies good for?

Answer 11

• Can provide extensive details on abnoramal outcomes and rare conditions

Question 12

Pitfalls of a case study

Answer 12

• Hard to replicate
• Hard to rule out other contributing factors

Question 13

What is relative risk (RR)?

Answer 13

Incidence in Exposed / Incidence in Unexposed

Question 14

Odds Ratio (OR)

Answer 14

Odds Ratio (OR) = Odds of outcome in Exposed / Odds of outcome in Unexposed

Question 15

What is Odds?

Answer 15

Odds = ( # cases ) / ( # non-cases )

Question 16

What Bias would this be an example of?

Subjects in study different to subjects not in studye.g. volunteers, cases referred from specialist clinics

Answer 16

Selection bias

Question 17

What bias would this be an example of?

Different processing for case & control samples Different interviewers

Answer 17

Measurement Bias

Question 18

What bias is this an example of?

Cases remember exposures better than controls? Cases exaggerate exposures more than controls

Answer 18

Recall bias

Question 19

What is the word for when factors may mask an actual association or, more commonly, falsely demonstrate an apparent association between the treatment and outcome when no real association between them exists.

Answer 19

Confounding factors