Research Study Design

Question 1

Name X4 types of study.

Answer 1

1) RCT
2) case-control
3) cohort
4) cross-sectional

Question 2

What is an RCT?

Answer 2

It is an interventional study where we randomly allocate treatment (new drug vs placebo or current gold standard).

Question 3

What is meant by efficacy?

Answer 3

How effective something is.

Question 4

Explain single vs double blinding.

Answer 4

Single = participants not informed about who is receiving which treatment

Double = neither participants nor assessors informed about who is receiving which treatment

Question 5

What is meant by intention to treat analysis?

Answer 5

It means ‘once randomised, always analysed’.

All participants randomised to a group are included in the analysis, specifically the analysis of the group to which they were randomised.

Question 6

What value indicates statistical significance?

Answer 6

A p-value < 0.05.

Question 7

What is a null hypothesis?

Answer 7

The hypothesis that there is NO significant difference between two comparisons.

Question 8

What does P<0.05 mean we can say about the null?

Answer 8

We can reject it as there is statistical significance.

Question 9

What implies clinical significance?

Answer 9

A change in measured outcome (usually a %).

E.g. a decrease in prevalence from 7.1% to 5.6%…

Question 10

What is a case-control study?

Answer 10

It is an observational study (no intervention).

Two groups are chosen, half with the disease that is being studied and the other half without.

Factors/causes of the disease are then increased investigated.

Question 11

What are some advantages of case-control studies?

Answer 11

They are retrospective, fast and inexpensive.

They are good for studying rare diseases as you can specifically select people with the disease.

Question 12

What are some disadvantages of case-control studies?

Answer 12

Data usually comes from records or the participants themselves, means information may be incomplete or bias.

Question 13

What is meant by odds ratio?

Answer 13

It is how many times more/less likely are you to find an exposure in someone with the disease than without.

E.g. if there is any odds ratio between cancer and smoking of 2.25, it means participants with cancer are 2.25 times more likely to be a smoker.

Question 14

An odds ratio value within what range would make you think there is a strong association between exposure and outcome?

Answer 14

> 1

Question 15

What is a cohort study?

Answer 15

It is an observational study (no intervention).

X2 groups of all healthy participants are chosen based if they have been exposed to a risk factor or not.

They are followed over time and their disease states monitored.

Question 16

What are some advantages of cohort studies?

Answer 16

They are less biased than case-control due to data being collected prospectively and not retrospectively, eliminating things such as recall bias.

They are good for studying rare exposures as you can specifically select people who have been exposed to said risk factors.

Question 17

What are some disadvantages of cohort studies?

Answer 17

You need large numbers of people to get enough developing the disease.

They often take a long time due to follow-ups (Framingham), which also may present issues keeping in touch with participants.

They will therefore also be expensive for the reasons above.

Question 18

What is a cross-sectional study?

Answer 18

It is an observational study (no intervention).

Participants have their data collected at a SINGLE POINT IN TIME.

Question 19

What are some reasons you would use a cross-sectional study?

Answer 19

To measure prevalence, views and attitudes etc…