Study Design

Question 1

What is the definition of a Case Report?

Answer 1

An article which describes and interprets an individual case

Question 2

What are often described in Case Reports?

Answer 2

Unique cases not explained by known diseases/syndromes
Cases that show important variation in a known disease/syndrome
Cases where a patient has 2 or more unexpected diseases/disorders

Question 3

What are the advantages of a Case Report?

Answer 3

Can identify new trends/diseases
Can detect new drug side effects
Educational
Identifies rare manifestations of disease

Question 4

What are the disadvantages of a Case Report?

Answer 4

May not be generalisable
Not based on systematic studies
May have other explanations
May emphasise misleading events

Question 5

What are the common pitfalls of Case Reports?

Answer 5

Patient should be described in detail
Observations should be carefully reported and unbiased
Only explore and infer - not confirm, deduce or prove

Question 6

What is the definition of a Case-Control Study?

Answer 6

Compares patients with disease (cases) with those who do not (controls)
Looks retrospectively to determine relationship between risk factor and disease

Question 7

What are the advantages of a Case-Control Study?

Answer 7

Good for rare diseases
Less time needed
Simultaneously look at multiple risk factors
Good for establishing association
Can answer questions unable to be answered otherwise

Question 8

What are the disadvantages of a Case-Control Study?

Answer 8

Issues with data due to recall bias
Not good for evaluating diagnostic methods
Can be difficult to find a suitable control group

Question 9

What are the common pitfalls of Case-Control Studies?

Answer 9

Need to be careful to avoid confounding - occurs when exposure and outcome are strongly associated with a third variable
Must use appropriate inclusion and exclusion criteria

Question 10

What is the definition of a Cohort Study?

Answer 10

One or more samples (cohort) are followed prospectively and status evaluations with respect to a disease/outcome are collected to determine what risk factors are associated with it

Question 11

What are the advantages of a Cohort Study?

Answer 11

Subjects in cohorts can be matched - limits influence of confounding variables
Standardisation of criteria/outcome possible
Easier and cheaper than RCT

Question 12

What are the disadvantages of a Cohort Study?

Answer 12

Cohorts can be hard to identify due to confounding variables
No randomisation - could result in imbalances in patient characteristics
Blinding/masking is difficult
Outcome of interest can take time to occur

Question 13

What are the common pitfalls of a Cohort Study?

Answer 13

Cohorts need to be chosen from similar but separate populations

Question 14

What is the definition of a RCT?

Answer 14

Randomly assigned participants into an experimental group or control group
Only expected difference between groups is the variable being tested

Question 15

What are the advantages of a RCT?

Answer 15

Good randomisation will eliminate population bias
Easier to blind/mask than observational studies
Results can be analysed using statistics

Question 16

What are the disadvantages of a RCT?

Answer 16

Expensive in time and money
Volunteer bias - may not represent population
Does not reveal causation
Loss to follow up

Question 17

What are the common pitfalls of RCT?

Answer 17

Should be of one population only

Variables being studied should be the only variable between groups

Question 18

What is the definition of a Practice Guideline?

Answer 18

Statement produced by a panel of experts outlining current best practice for health professionals and patients

Question 19

What are the advantages of Practice Guidelines?

Answer 19

Created by experts
Based on published literature
Considered an evidence based resource

Question 20

What are the disadvantages of Practice Guidelines?

Answer 20

Slow to change/update
Not always available
Expensive and time consuming to produce

Question 21

What is the definition of a Systematic Review?

Answer 21

Document often written by a panel providing a comprehensive review of all relevant literature on a particular topic

Question 22

What are the advantages of a Systematic Review?

Answer 22

Exhaustive - current literature, unpublished studies, ongoing research
Less costly than a new study
Results can be generalised and extrapolated
More reliable and accurate than individual studies
Considered an evidence based resource

Question 23

What are the disadvantages of a Systematic Review?

Answer 23

Very time consuming

May not be easy to combine studies

Question 24

What are the common pitfalls of Systematic Reviews?

Answer 24

Studies included should have varying designs but studying the same outcome

Question 25

What is the definition of a Meta-Analysis?

Answer 25

Systematically combining quantitative and qualitative data from multiple studies to create a single conclusion with greater statistical power

Question 26

What are the advantages of a Meta-Analysis?

Answer 26

Greater statistical power
Greater ability to extrapolate
Considered an evidence based resource

Question 27

What are the disadvantages of a Meta-Analysis?

Answer 27

Difficult and time consuming to identify appropriate studies

Requires advances statistical techniques

Question 28

What are the common pitfalls of Meta-Analyses?

Answer 28

Studies pooled should be of similar type i.e. all RCTs

Should include published and unpublished literature to avoid publication bias

Question 29

What technique can be used to help ensure that the participants are randomly assigned to either control or intervention group?

Answer 29

Allocation concealment