ERIC: Common Measures & Stats

Question 1

Measures of Frequency (ERIC)

Answer 1

1 of 4 common epi measures

how often something occurs

(not a proportion like in bio)

Question 2

3 common frequency measures (ERIC)

Answer 2

1. risk/”incidence”
2. rate/”incidence rate”
3. prevalence

Question 3

Risk/”incidence” forumula (ERIC)

Answer 3

1 of 3 common frequency measures

of new cases this year/total population this year = part:whole of cases this year

Question 4

Another name for risk/”incidence”

Answer 4

attack rate…which isn’t actually a rate gah! (is also know as…)

Question 5

Risk/”incidence” definition (ERIC)

Answer 5

1 of 3 common frequency measures

probability of an unaffected person developing a health outcome/dx, during a given time period

Question 6

“Incidence rate” definition (ERIC)

Answer 6

1 of 3 common frequency measures

describes how quickly a health outcomes is moving through a population in terms of # of cases and person-time

Question 7

“Incidence rate” formula (ERIC)

Answer 7

1 of 3 common frequency measures

of NEW cases/total amount of time that each participant in a study contributed to the study

Question 8

Prevalence definition (ERIC)

Answer 8

1 of 3 common frequency measures

proportion of population that already has a dx/health outcome

Question 9

Prevalence formula (ERIC)

Answer 9

1 of 3 common frequency measures

of affected individuals/total populations

Question 10

Measures of Association (ERIC)

Answer 10

1 of 4 common epi measures

used to compare relationships/impacts between various specific exposures and health outcomes

Question 11

Measures of Significance (ERIC)

Answer 11

1 of 4 common epi measures

p-value (usually 0.5) threshold used to determine whether an association between an exposure and health outcome valid or just d/t chance

Question 12

Measures of Precision (ERIC)

Answer 12

1 of 4 common epi measures

shows how precise data measurements are

(by using confidence intervals (ranges of uncertainty) to express the variability in means, risks ratios, rate ratios, odds ratios, etc calculated for a study)

Question 13

4 types of Measures of Association (ERIC)

Answer 13

1. risk difference
2. risk ratio
3. rate ratio
4. odds ratio

Question 14

Risk difference formula

Answer 14

1 of 4 types of measures of association

(# of cases in exposed group/total # at risk in exposed group)/(# of cases in control group/total # at risk in control group)

Question 15

Risk ratio formula

Answer 15

1 of 4 types of measures of association

RATIO of risk in exposed group : risk in unexposed/control group

Ratio > 1 = exposure has harmful effect
Ratio < 1 = exposure has protective effect

Question 16

Rate ratio formula

Answer 16

1 of 4 types of measures of association

RATIO of the RATE in exposed group : Rate in unexposed/control group

Ratio > 1 = exposure has harmful effect
Ratio < 1 = exposure has protective effect

Question 17

Odds ratio formula

Answer 17

1 of 4 types of measures of association

Question 18

Risk difference definition

Answer 18

1 of 4 types of measures of association

aka “attributable risk”; compares risk differentials between groups to show how much risk is d/t an exposure under investigation

Question 19

Risk ratio definition

Answer 19

1 of 4 types of measures of association

describe/measure the strength of an association between an exposure and a health outcome (in terms of risk)

Question 20

Rate ratio definition

Answer 20

1 of 4 types of measures of association

describe/measure the strength of an association between an exposure and a health outcome (in terms of rate)

Question 21

Odds ratio definition

Answer 21

1 of 4 types of measures of association

an approximation of risk ratio or rate ration for the purposes of use in cohort studies (allowing researchers to generalize results to broader populations?)

Question 22

2 possible outcomes of risk difference assessment

Answer 22

1. Positive difference- exposure in question confers higher risk of a specific health outcome
2. Negative difference- exposure in question confers protective effect against a specific health outcome

Question 23

Null value

Answer 23

A risk, rate, and/or odds ratio value to suggests the exposure in question has not effect on/association with health outcome at all.

Usually equals 1.0 but thresholds are set based on the nature of the study

Question 24

Null hypothesis

Answer 24

proposes that there is no association between an exposure and health outcome under question

Question 25

Confidence Interval

Answer 25

method for expressing uncertainty; large/wide intervals bad, small/tight intervals good

involves a range of plausible values for the measure of an association (i.e. between and exposure and a health outcome)

Question 26

Point estimate

Answer 26

research/statistics jargon

a specific value used to estimate a mean, standard deviation, etc for a population characteristic under investigation

i.e. risk ratio, rate ratio, or odds ratio

Question 27

Parameter

Answer 27

research/statistics jargon

a measurable characteristic of a population, such as a mean or a standard deviation

Question 28

2 common types of epi measurement estimates (ERIC)

Answer 28

1. crude values

2. adjusted values

Question 29

Crude estimates

Answer 29

1 of 2 common types of epi measurement estimates

involves raw numbers/counts w/o nuance (such as differences between different sub-pops within the counted pop)

Question 30

Adjusted estimates

Answer 30

1 of 2 common types of epi measurement estimates

involves making adjustments to raw numbers/counts so that the impact of differences sub-pops within the counted pop can be accounted for)