1|Page
ACVPM Epidemiology And Biostats
|Actual Questions And Answers 2026
Define epidemiology - correct-answer -largely concerned with disease prevention
and therefore with the succession of events which result in the exposure of
specific types of individual to specific types of environment. Epidemiologists ID
exposures and evaluate associations with health, welfare, productivity and other
outcomes of interest
what is the major difference between epidemiologists and laboratory scientists? -
correct-answer -epidemiologists study health and disease outcomes in the real
world (under field conditions)
what is the primary study design of epidemiology - correct-answer -observational
define inductive reasoning - correct-answer -process of making generalized
inferences about causation based on repeated observations
,2|Page
define deductive reasoning - correct-answer -process of inferring general law of
nature exists and has application in specific or local instance where a hypothesis
about a law of nature starts and observations are made to challenge the law
define what a cause is in epidemiology - correct-answer -a cause is any factor that
produces a change in the severity or frequency of the outcome
define the component-cause model - correct-answer -based on concepts of
necessary and sufficient causes developed by Rothman in 1976. Necessary cause
is one without which the disease CANNOT occur (the factor will ALWAYS be
present if the dz occurs). Sufficient cause always producers the disease (if the
factor is present, DZ will follow). Component-cause is one of a NUMBER of factors
that in COMBINATION constitute a sufficient cause. Factors may be present
simultaneously or in sequence.
what are termed as survival data - correct-answer -time to event data (outcome of
interest is time until death)
what are characteristics of survival data? - correct-answer -1) strict left truncation
2) right skew distribution 3) censored
,3|Page
how to quantify time to event in survival analysis? - correct-answer -1. mean time
to event 2. median time to event 3. overall probability of event 4. n-year survival
risk 5. incidence rate
define right, interval and left censoring - correct-answer -right: when animal is not
observed when event occurs (most common - lost to followup) interval: when
animal is observed periodically left: similar to interval except interval occurs at
start of the study
define truncation in survival data - correct-answer -refers to periods of time in
which nothing is known about the animal in terms of whether or not the event
occurred (periods of time are gaps - like multiple events occur)
right truncation=right censoring, interval truncation = truncation occurs
throughout, left truncation = at the start
what are the general approaches to analyzing survival data - correct-answer -non-
parametric, semi-parametric, parametric models
what are non-parametric methods for survival analysis - correct-answer -1)
actuarial life tables 2) Kaplan-Meier estimator of survivor function or the product-
limit estimate 3) Nelson -Aalen estimator of cumulative hazard function
, 4|Page
advantages of Kaplan-Meier estimator over actuarial life tables - correct-answer -
1) avoids assumption that withdrawal occurred uniformly throughout the interval
2) does not assume that risk if constant over the arbitrarily selected interval
3) still assumes that withdrawals have same outcomes as those observed
define cumulative hazard function of Nelson-Aalen model - correct-answer -
expected number of outcomes for one animal occurring up to a point in time
(assume that outcome could occur multiple times in an animal)
define survivor, failure, prob density function in survival analysis - correct-answer -
1) survivor function = prob that an animal's survival time will exceed some
specified time t 2) failure = prob of not surviving past time t 3) probability density
= describes distribution of survival times and is the slope (derivative) of failure
function
define hazard, cumulative hazard function in survival analysis - correct-answer -1)
hazard= prob an event occurs at time t given that it has not occurred up to time t -
can also be calculated as the ratio of prob density and survival function 2)
cumulative or integrated hazard represents the accumulation of hazard across
time (integral of hazard function)
ACVPM Epidemiology And Biostats
|Actual Questions And Answers 2026
Define epidemiology - correct-answer -largely concerned with disease prevention
and therefore with the succession of events which result in the exposure of
specific types of individual to specific types of environment. Epidemiologists ID
exposures and evaluate associations with health, welfare, productivity and other
outcomes of interest
what is the major difference between epidemiologists and laboratory scientists? -
correct-answer -epidemiologists study health and disease outcomes in the real
world (under field conditions)
what is the primary study design of epidemiology - correct-answer -observational
define inductive reasoning - correct-answer -process of making generalized
inferences about causation based on repeated observations
,2|Page
define deductive reasoning - correct-answer -process of inferring general law of
nature exists and has application in specific or local instance where a hypothesis
about a law of nature starts and observations are made to challenge the law
define what a cause is in epidemiology - correct-answer -a cause is any factor that
produces a change in the severity or frequency of the outcome
define the component-cause model - correct-answer -based on concepts of
necessary and sufficient causes developed by Rothman in 1976. Necessary cause
is one without which the disease CANNOT occur (the factor will ALWAYS be
present if the dz occurs). Sufficient cause always producers the disease (if the
factor is present, DZ will follow). Component-cause is one of a NUMBER of factors
that in COMBINATION constitute a sufficient cause. Factors may be present
simultaneously or in sequence.
what are termed as survival data - correct-answer -time to event data (outcome of
interest is time until death)
what are characteristics of survival data? - correct-answer -1) strict left truncation
2) right skew distribution 3) censored
,3|Page
how to quantify time to event in survival analysis? - correct-answer -1. mean time
to event 2. median time to event 3. overall probability of event 4. n-year survival
risk 5. incidence rate
define right, interval and left censoring - correct-answer -right: when animal is not
observed when event occurs (most common - lost to followup) interval: when
animal is observed periodically left: similar to interval except interval occurs at
start of the study
define truncation in survival data - correct-answer -refers to periods of time in
which nothing is known about the animal in terms of whether or not the event
occurred (periods of time are gaps - like multiple events occur)
right truncation=right censoring, interval truncation = truncation occurs
throughout, left truncation = at the start
what are the general approaches to analyzing survival data - correct-answer -non-
parametric, semi-parametric, parametric models
what are non-parametric methods for survival analysis - correct-answer -1)
actuarial life tables 2) Kaplan-Meier estimator of survivor function or the product-
limit estimate 3) Nelson -Aalen estimator of cumulative hazard function
, 4|Page
advantages of Kaplan-Meier estimator over actuarial life tables - correct-answer -
1) avoids assumption that withdrawal occurred uniformly throughout the interval
2) does not assume that risk if constant over the arbitrarily selected interval
3) still assumes that withdrawals have same outcomes as those observed
define cumulative hazard function of Nelson-Aalen model - correct-answer -
expected number of outcomes for one animal occurring up to a point in time
(assume that outcome could occur multiple times in an animal)
define survivor, failure, prob density function in survival analysis - correct-answer -
1) survivor function = prob that an animal's survival time will exceed some
specified time t 2) failure = prob of not surviving past time t 3) probability density
= describes distribution of survival times and is the slope (derivative) of failure
function
define hazard, cumulative hazard function in survival analysis - correct-answer -1)
hazard= prob an event occurs at time t given that it has not occurred up to time t -
can also be calculated as the ratio of prob density and survival function 2)
cumulative or integrated hazard represents the accumulation of hazard across
time (integral of hazard function)
