# Chapter 9: Measures of Effect Flashcards

What is an effect measure?

a quantity that measures the effect of a factor on the frequency or risk of a health outcome

- Attributable fractions: measure the fraction of cases due to a factor
- Absolute effects: risk and rate differences measure the amount of a factor adds to the risk or rate of a disease
- Relative effects: risk and rate ratios measure the amount by which a factor multiplies the risk or rate of disease

What is the difference measure of association?

a type of comparison. Used to compare the disease burden in 2 groups. A way to do that is to calculate the absolute difference in disease frequency

What is another name for difference measure of association?

Attributable risk

Risk difference?

the difference between the incidence rate of disease in an exposed group and a non exposed group

-RD= I(e)-I(ne)

Population risk difference?

a measure of the benefit to the population derived by modifying a risk factor

-I(p)total incidence rate= I(e)P(e)+ I(ne)P(ne)*

What is an etiologic fraction? Equation?*

defined as the proportion of the rate in the exposed group that is due to the exposure

-(I(e)-I(ne)/I(e)) page 950

Another name for etiologic fraction?

Attributable proportion/fraction

Population fractions?***

page 955-957

What is a null hypothesis?

there is no difference in pop. parameters among the groups being compared

P value?

indicates the probability that the findings observed could have occurred by chance alone

What is a confidence interval?

a CI is a statisitical measure. Computed interval of values that w/ a given probability, contains the true value of the population parameter/estimate

-Can be calculated for odds ration as well as other relative risks, etc.

What is a deterministic model?

it claims that a cause is invariably followed by an effect

- Ex: laws related to gravitation, motion, electrostatics
- from the philosophy of determinism

What is a necessary cause?

a factor whose presence is “required” for the occurrence of the effect

What is a sufficient cause?

a cause that is sufficient by itself to produce the effect

Deterministic causality?

- necessary and sufficient
- necessary but not sufficient
- sufficient but not necessary
- neither necessary nor sufficient
- pages 978-979