EIP - Rates, Ratios and Risks - Week 10

Question 1

What can cross sectional studies be used for (2)?

Answer 1

Generate questions about the relationship between disease and possible causes
Estimate the prevalence of a health condition in a population

Question 2

Is there an implication of cause and effect in cross sectional studies?

Answer 2

No

Question 3

True or false

Cohort studies are usually prospective

Answer 3

True

Question 4

Are cohort studies longitudinal? what about cross sectional studies?

Answer 4

Cohort studies are

Cross sectional studies arent

Question 5

What is an odds ratio and what does it represent?

Answer 5

A comparison of the odds of something being in two different grouos
It gives the odds of something being true in one group compared to another

Question 6

Are odds the same as probabilities? What about relative risk?

Answer 6

It is not the same as probabilities, and therefore not the same as relative risk

Question 7

What does relative risk imply we know?

Answer 7

Incidence

Question 8

What kind of studies can relative risk be used in and why?

Answer 8

Longitudinal studies because you need incidence in both groups not just prevalence

Question 9

What studies should odds ratios be used in?

Answer 9

Cross sectional studies

Question 10

Describe a case control study. Is it retrospective or prospective?

Answer 10

You start with the state under investigation already present and go back and try identify the cause, so it is retrospective

Question 11

What are case control studies useful for?

Answer 11

Hypothesis generation

Question 12

Can case control studies answer questions about causation?

Answer 12

No, its too prone to bias

Question 13

Define control event rate.

Answer 13

Probability of developing an outcome for the control group

Question 14

Define experimental event rate.

Answer 14

The probability of developing an outcome for the treatment group

Question 15

Define relative risk.

Answer 15

The ratio of the probability of developing an outcome among those receiving the treatment of interest or exposed to a risk factor, compared with the probability of developing the outcome if the intervention or risk factor is not present.

Question 16

Define relative risk reduction.

Answer 16

The extent to which a treatment reduces a risk, in comparison with patients not receiving the treatment of interest.

Question 17

Define absolute risk reduction.

Answer 17

The difference in the rates of adverse events between experimental and control groups.

Question 18

What is meant by number needed to treat?

Answer 18

The number of patients who must be exposed to an intervention before the outcome of interest occurred (e.g. the number of patients needed to treat to prevent one adverse outcome).