# EIP - Rates, Ratios and Risks - Week 10 Flashcards Preview

## OD2 - Applied Clinical Training & Research Studies in Vision and Optometry > EIP - Rates, Ratios and Risks - Week 10 > Flashcards

Flashcards in EIP - Rates, Ratios and Risks - Week 10 Deck (18)
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1
Q

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

A

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

2
Q

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

A

No

3
Q

True or false

Cohort studies are usually prospective

A

True

4
Q

Are cohort studies longitudinal? what about cross sectional studies?

A

Cohort studies are

Cross sectional studies arent

5
Q

What is an odds ratio and what does it represent?

A

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

6
Q

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

A

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

7
Q

What does relative risk imply we know?

A

Incidence

8
Q

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

A

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

9
Q

What studies should odds ratios be used in?

A

Cross sectional studies

10
Q

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

A

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

11
Q

What are case control studies useful for?

A

Hypothesis generation

12
Q

Can case control studies answer questions about causation?

A

No, its too prone to bias

13
Q

Define control event rate.

A

Probability of developing an outcome for the control group

14
Q

Define experimental event rate.

A

The probability of developing an outcome for the treatment group

15
Q

Define relative risk.

A

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.

16
Q

Define relative risk reduction.

A

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

17
Q

Define absolute risk reduction.

A

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

18
Q

What is meant by number needed to treat?

A

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).