Research methods

Question 1

What is a type I error?

Answer 1

Finding an association that does not exist.

Question 2

What is a type II error?

Answer 2

Finding no association when an association actually does exist.

Question 3

What is colinearity?

Answer 3

When two explanatory variables are highly correlated

Question 4

What is colinearity?

Answer 4

When two explanatory variables are highly correlated

Question 5

What are confounding variables?

Answer 5

Two explanatory variables which are both related to the outcome of each other.

Question 6

What is an explanatory variable?

Answer 6

Independent variable.

Question 7

What is an observational study? What are the three types of observational study?

Answer 7

Observe exposure and outcome in different groups.

• Cohort study= following X and Y groups until something happens.
• Cross sectional study=collecting data all from one time point.
• Case control study= retrospectively analysing what one group was exposed to more than the control.

Question 8

What is an experimental study? What is one benefit of using an experimental study?

Answer 8

Manipulating variables of interest and observing the outcome.

It allows us to see causality, this can never be seen with observational studies.

Question 9

Statistically speaking, why should we use replication in our studies?

Answer 9

A larger sample size/ study being done more times and more data being collected increases the power to detect important increases/ decreases/changes.

Question 10

What is the power value we use that is equivalent to a 95% confidence interval?

Answer 10

0.8

Question 11

What does a power value of 0.8 mean?/ How can we interpret this?

Answer 11

We are 80% sure that there has been no type II error (finding no association when there actually is an association).

Question 12

What is done in a retrospective study?

Answer 12

Comparing control groups with people with a group of people with an outcome of interest.

Question 13

What questions do we ask to ensure a study has validity?

Answer 13

Pre study

• Why this location
• Why this (sub)population
• Does the study design make sense

Mid study

• Why this end point (e.g. DALY over morbidity)
• Why this sample size
• Why this duration

Post study

• Why this method of displaying results
• Why this stats test
• Why this conclusion

Question 14

What are the three qualities we want in our study to make it a good study?

Answer 14

Validity, importance and generalisability

Question 15

Why do we want a generalisable study?

Answer 15

Allows us to inform different systems, don’t want to to be too specific for only one location/population etc.

Question 16

What does the importance of a study tell us?

Answer 16

Tells us the playoff between statistically significant data and the effect size- does it only have a very small effect size , is this effect worthwhile?

Question 17

What are the three ethical principles we must abide by?

Answer 17

1. Autonomy/ respect for other persons
2. Benevolence/ non-maleficence
3. Justice/ equality among individuals.

Question 18

What did the Nuremberg code emphasise?

Answer 18

Voluntary participation

Question 19

What does the declaration of Helsinki emphasise?

Answer 19

Looks at risk and benefit and safeguarding participants.

Question 20

What is an impartial witness?

Answer 20

Someone who signs on behalf of someone else in areas of illiteracy- they must be IMPARTIAL i.e. not part of study group and not paid. They countersign the participant’s finger print.

Question 21

What is the age of consent and what is the exception to this?

Answer 21

18 unless an emancipated minor.

Question 22

What are the 7 ethical requirements?

Answer 22

1. Social and scientific value
2. Scientific validity
3. Fair participant selection
4. Favourable risk-benefit ratio
5. Independent review
6. Informed consent
7. Respect (potential and involved participants)