EPID 7020 Midterm Study Questions with Correct Answers
True or False: When calculating the incidence rate of a disease, you exclude from the calculation
persons who had disease at the start of the risk period. - Answers True
Multiple Choice: When disease incidence and disease duration is stable, prevalence will..
A. Increase with increasing disease incidence and decrease with increasing disease duration.
B. Decrease with increasing disease incidence and increase with increasing disease duration.
C. Increase with increasing disease incidence and increase with increasing disease duration.
D. Increase with decreasing disease incidence and increase with decreasing disease duration. -
Answers C. Increase with increasing disease incidence and increase with increasing disease
duration.
Short Answer: Out of the four methods used to estimate incidence proportions which method
can not be used when follow up is incomplete? - Answers Incidence Density Method
Consider a study researching the flu was conducted with a sample size of 350 over a year.
During this study, 30% of the sample contracted the flu. What is the incidence rate of this study?
- Answers 0.3 cases of influenza per one year of person-time
Prevalence is influenced by:
a. disease incidence
b. study duration
c. disease risk
d. initial sample size - Answers a. disease incidence
True or False: In an open population no new members can be added in over time. - Answers
False
True or False: A closed population is a type of population where individuals can join or leave a
study throughout the time period that the study is ongoing. - Answers False
Short Answer: Why would an individual choose to measure the incidence proportion rather than
the incidence density? - Answers - easier to understand
- predicts individual risk
- understand cumulative frequency of disease occurrence when risk overtime is not uniform
Short Answer: What does it mean when we say "the Classic Life Table is just a special case of
, the Kaplan-Meier curve"? - Answers ????
Multiple Select: If the number of people entering a population is balanced by the number exiting
the population in any
period of time within levels of age, sex, and other determinants of risk, the population is ....
a) open
b) closed
c) steady - Answers a) open
c) steady
Short Answer: In a 4-year longitudinal study of cardiovascular disease among 8,000 adults, the
exact date of disease onset is not known. Instead, the researchers have yearly data on the
number of new cases for each year of follow-up. Additionally, some participants leave the study
for unknown reasons, and their data is censored. The researchers want to estimate the annual
probability of developing cardiovascular disease in this population.Which method should be
used for calculating incidence proportion and why? - Answers The method used should be the
Classic Life Table Approach because it doesn't require exact time of events, handles censored
observations, and can measure incidence proportion over long follow-up intervals
Short Answer: How does the use of aggregate data versus individual-level data in the incidence
density method, which estimates incidence proportion from incidence rate data, impact the
assumption of uniformity of losses? - Answers ???
True or False: An assumption for incidence proportion is that risk remains constant over the
follow-up period. - Answers True
True or False: The risk ratio and risk difference, when derived from incidence proportions, are
constrained to an asymmetric range between 0 and 1. - Answers False
True or False: If disease incidence is static, disease prevalence will increase as duration
decreases. - Answers False
True or False: The time-period that is captured by an exposure variable must include the time
immediately before the risk period. - Answers True
Multiple Choice: What does the term "available dose" refer to in exposure measurement?
a) The amount of exposure absorbed by the body
b) The concentration of an agent in the subject's external environment
c) The total duration of exposure
True or False: When calculating the incidence rate of a disease, you exclude from the calculation
persons who had disease at the start of the risk period. - Answers True
Multiple Choice: When disease incidence and disease duration is stable, prevalence will..
A. Increase with increasing disease incidence and decrease with increasing disease duration.
B. Decrease with increasing disease incidence and increase with increasing disease duration.
C. Increase with increasing disease incidence and increase with increasing disease duration.
D. Increase with decreasing disease incidence and increase with decreasing disease duration. -
Answers C. Increase with increasing disease incidence and increase with increasing disease
duration.
Short Answer: Out of the four methods used to estimate incidence proportions which method
can not be used when follow up is incomplete? - Answers Incidence Density Method
Consider a study researching the flu was conducted with a sample size of 350 over a year.
During this study, 30% of the sample contracted the flu. What is the incidence rate of this study?
- Answers 0.3 cases of influenza per one year of person-time
Prevalence is influenced by:
a. disease incidence
b. study duration
c. disease risk
d. initial sample size - Answers a. disease incidence
True or False: In an open population no new members can be added in over time. - Answers
False
True or False: A closed population is a type of population where individuals can join or leave a
study throughout the time period that the study is ongoing. - Answers False
Short Answer: Why would an individual choose to measure the incidence proportion rather than
the incidence density? - Answers - easier to understand
- predicts individual risk
- understand cumulative frequency of disease occurrence when risk overtime is not uniform
Short Answer: What does it mean when we say "the Classic Life Table is just a special case of
, the Kaplan-Meier curve"? - Answers ????
Multiple Select: If the number of people entering a population is balanced by the number exiting
the population in any
period of time within levels of age, sex, and other determinants of risk, the population is ....
a) open
b) closed
c) steady - Answers a) open
c) steady
Short Answer: In a 4-year longitudinal study of cardiovascular disease among 8,000 adults, the
exact date of disease onset is not known. Instead, the researchers have yearly data on the
number of new cases for each year of follow-up. Additionally, some participants leave the study
for unknown reasons, and their data is censored. The researchers want to estimate the annual
probability of developing cardiovascular disease in this population.Which method should be
used for calculating incidence proportion and why? - Answers The method used should be the
Classic Life Table Approach because it doesn't require exact time of events, handles censored
observations, and can measure incidence proportion over long follow-up intervals
Short Answer: How does the use of aggregate data versus individual-level data in the incidence
density method, which estimates incidence proportion from incidence rate data, impact the
assumption of uniformity of losses? - Answers ???
True or False: An assumption for incidence proportion is that risk remains constant over the
follow-up period. - Answers True
True or False: The risk ratio and risk difference, when derived from incidence proportions, are
constrained to an asymmetric range between 0 and 1. - Answers False
True or False: If disease incidence is static, disease prevalence will increase as duration
decreases. - Answers False
True or False: The time-period that is captured by an exposure variable must include the time
immediately before the risk period. - Answers True
Multiple Choice: What does the term "available dose" refer to in exposure measurement?
a) The amount of exposure absorbed by the body
b) The concentration of an agent in the subject's external environment
c) The total duration of exposure
