Design Strategies and Statistical Methods in Descriptive Epidemiology

Question 1

Study design

Answer 1

program that directs the researcher along the path of systematically collecting, analyzing, and interpeting data

Question 2

Descriptive epidemiology

Answer 2

organizes, summarizes, and describes epidemiologic data by person, place, and time; characterizes the distribution of health-reltaed states/events by who, what, when, where

Question 3

Types of descriptive studies

Answer 3

ecologic studies
case reports
case series
cross-sectional surveys

Question 4

Ecologic

Answer 4

involves aggregate data and makes comparisons across large populations

Question 5

Case reports

Answer 5

involves profile of a single individual

Question 6

Case series

Answer 6

involves small gorup of patients with similar dx

Question 7

Cross sectional survey

Answer 7

conduted over a short period of time with no follow-up period and the unit of analysis is the individual

Question 8

Serial survey

Answer 8

cross-sectional surveys that are routinely conducted

Question 9

Common serial surveys include

Answer 9

US census, Behavioral Risk Factor Surveillance System

Question 10

Types of data

Answer 10

Nominal
Ordinal
Discrete
Continuous

Question 11

Nominal examples

Answer 11

sex, diseases (yes/no), race, marital status, education status

Question 12

Ordinal examples

Answer 12

preference rating (agree, neutral, disagree)

Question 13

Discrete examples

Answer 13

number of cases

Question 14

Continuous examples

Answer 14

dose of ionzing radiation

Question 15

Nominal

Answer 15

Categorical – unordered categories

Question 16

Ordinal

Answer 16

Categorgical – ordering informative

Question 17

Discrete

Answer 17

Quantitative – integers

Question 18

Continuous

Answer 18

Quantitative – values on a continuum

Question 19

Ratio formula

Answer 19

X/Y x 10^

Question 20

Ratio

Answer 20

the values of x and y are independent; x is not contained in y; rate base is 1

Question 21

Proportion

Answer 21

x is contained in y; typically expressed as a %; rate base is 100

Question 22

Rate

Answer 22

a proportion with the addition that it represents the number of health-related states or events in a population over a specified time period

Question 23

Rate equations

Answer 23

incidence rate
mortality rate
attack rate
person-time rate
secondary attack rate
prevalence proportion
case-fatality rate

Question 24

Incidence rate

Answer 24

new cases / population at risk x 10n

Question 25

Mortality rate

Answer 25

deaths during a period/population from which death occured x 10n

Question 26

Attack rate

Answer 26

new cases occuring during a short-time period / population at risk x 10n

Question 27

Person-time rate

Answer 27

number of cases during observation period / time each person observed totalled for all persons x 10n

Question 28

Secondary attack rate

Answer 28

new cases among contacts of primary cases / poplation at beginning of time-period - primary cases x 10n

Question 29

Prevelenace population

Answer 29

new and existing cases of disease / total study of population x 10n

Question 30

Attack rate (cumulative incidence rate)

Answer 30

diseases or events that affect a larger group of the population

Question 31

Crude rate is calculated without any _____ and is limited upon comparison between_____ because of _____.

Answer 31

restrictions (age or sex) on who is counted in the numerator or denominator; subgroups of the population; confounding factors (age-distribution between groups)

Question 32

Age-adjusted Rate

Answer 32

adjusting for differences in the age distribution among a population to eliminate confounding factors

Question 33

Two methods for calculating age-adjusted rates

Answer 33

direct and indirect

Question 34

SMR

Answer 34

standarized morbidity ratio

Question 35

SMR formula

Answer 35

SMR = Observed/expected

Question 36

confounding

Answer 36

the distortion of the association between an exposure and health outcome by an extraneous, third variable

Question 37

confounding examples

Answer 37

age sex educational level smoking

Question 38

confounder (confounding variable/lurking variable)

Answer 38

an extrinsic variable that distorts the outcome of what is being studied

Question 39

spurious association

Answer 39

caused by a third factor (confounder) that is not apparent at the time of examination