34. TYPES OF STUDY DESIGNS

Question 1

1. What kind of study design is it:

When the Researcher has had some kind of intervention on the patients?

Answer 1

• Interventional Study

Question 2

2. What kind of study design is it:

When the Researcher has not had any kind of intervention on the patients?

Answer 2

• Observational Study

Question 3

3. What kind of study design is it:

When the study is randomised and a control group is present?

Answer 3

• a Randomised Controlled Trail
• this is a type of Interventional Study

Question 4

4. What kind of study design is it:

When the study is not randomised and there is no control group is present?

Answer 4

• a Non-randomised, non-controlled Trail
• this is a type of Interventional Study

Question 5

5. What kind of study design is it:

When there is an Assessment of the Exposure-Outcome association?

Answer 5

• an Analytic Study
• this is a type of Observational Study

Question 6

6. What kind of study design is it:

When there is not an Assessment of the Exposure-Outcome association?

Answer 6

• a Descriptive Study
• this is a type of Observational Study

Question 7

7. What kind of study design is it:

When the study times the assessed exposure before the Outcome?

Answer 7

• a Cohort Study
• this is a type of Analytic Study

Question 8

8. What kind of study design is it:

When the study times the assessed exposure after the Outcome?

Answer 8

• a Case-Control Study
• this is a type of Analytic Study

Question 9

9. What kind of study design is it:

When the study times the assessed exposure simultaneously with the Outcome?

Answer 9

• a Cross-Sectional Study
• this is a type of Analytic Study

Question 10

10. What are the 2 types of Cross-Sectional Studies?

Answer 10

1. Descriptive
2. Analytic

Question 11

11. What is a Descriptive Cross-Sectional Study?

Answer 11

• it is when the study assesses only one variable at a
  time

EXAMPLE:
- the prevalence of breast Cancer in Cyprus

Question 12

12. What is an Analytic Cross-Sectional Study?

Answer 12

• this is when the study assesses an association between
  two variables at the same time

EXAMPLE:
- if there is an association between breastfeeding and
breast cancer in Cyprus?

Question 13

13. What kind of sample is recruited for a
    Cross-Sectional Study?

Answer 13

• a Random sample
• it is recruited from the Source Population

Question 14

14. How are the assessment performed in a Cross-Sectional Study?

Answer 14

• they are performed at a specific point in time
• they can also happen over a short duration of time

THIS MEANS THAT:
- in the case of Analytical Cross-Sectional Studies
- the exposure and the outcome are assess
simultaneously

Question 15

15. What kind of exposures do Cross-Sectional studies deal with?

Answer 15

• they measure present exposures

SOME ASSESSMENTS:
- may deal with past exposures
- EG: the birth weight of an individual

Question 16

16. With regards to Cross-Sectional studies, what can be said about the form that they take in many countries?

Answer 16

• they take the form of surveys
• these annual and bi-annual cross-sectional studies
• these assess the health of the population

THIS HEALTH IS ASSESSED IN TERMS OF:
- major diseases
- health behaviours

Question 17

17. What are the three descriptive measures associated with Cross-sectional Studies?

Answer 17

1. PROPORTIONS
   - these deal with categorical variables
2. PREVALENCE
   - these deal with Binary Categorical Variables
3. MEAN AND MEDIUM
   - these deal with numeric variables

Question 18

18. What are the Measures of Association related to Cross-Sectional Studies?

Answer 18

1. ODDS RATIO
   - these deal with Binary Categorical Outcomes
2. MEAN DIFFERENCE
   - these deal with Categorical Exposures and Numeric
   Outcomes
3. REGRESSION AND CORRELATION COEFFICIENTS
   - these deal with Numeric Exposures and Numeric
   Outcomes

Question 19

19. What are the 3 advantages of Cross-Sectional Studies?

Answer 19

1. They are easy to perform
2. They are less costly
3. They provide the opportunity to readily assess the
   prevalence of a disease or an association in the
   population
   - the results will have a high relevance for Public Health

Question 20

20. What are the 4 disadvantages of a Cross-Sectional Study?

Answer 20

1. IT IS AN OBSERVATIONAL DESIGN
   - it is prone to information bias
   - this is because the measurements are based on
   self-reports and questionnaires
2. IT IS AN OBSERVATIONAL DESIGN
   - it is prone to Confounding
   - this is because it is not always possible to assess all
   the potential confounders
3. IT IS IMPOSSIBLE TO ASSESS THE RISK (INCIDENCE) OF
   THE DISEASE
4. IT IS IMPOSSIBLE TO ESTABLISH TEMPORALITY IN AN
   ASSOCIATION
   - this is because the exposure and the outcome are
   assessed simultaneously
5. IT IS NOT APPROPRIATE
   - for seeing how much of an effect the exposure has in
   causing the outcome
6. IT HAS A HIGH LIKELIHOOD OF REVERSE CAUSATION