NR503 Mid-Term Study Guide
1. Understand and compare the different measures of morbidity (p. 41-58)
Incidence rate is defined as the number of new cases of a disease that occur during a
specified period of time in a population at risk for developing the disease. Incidence rate
per 1,000=
No. of new cases of a disease occurring in the population during a specified period of
time/No. Of persons who are at risk of developing the disease during that period of time X
1,000. Incidence is a measure of events; measure of risk (transition from non-diseased to
diseased).
Prevalence is defined as the number of affected persons present in the population at a
specific time divided by the number of persons in the population at that time. What
proportion of the population is affected by the disease at that time? No. of cases with
disease/No. Of persons in the population X 1,000. We don’t determine when the disease
developed; just a snapshot of who has it at that time. We can’t account for duration of the
disease.
a. Incidence and prevalence
i. Define
ii. Understand why data are important for measuring risk
iii. Interpret findings
iv. Understand the relationship between incidence and prevalence and impact of each on
duration of disease
Prevalence=Incidence X Duration of Disease
v. Calculate incidence rate
vi. Calculate prevalence rate
vii.Relationship between prevalence, incidence, and mortality
Prevalence and incidence are related by the duration of disease. If incidence is increasing
over time, then duration of illness has to decrease in order to keep the prevalence rate
constant. This may occur through better treatments to cure disease or through higher case-
1. Understand and compare the different measures of morbidity (p. 41-58)
Incidence rate is defined as the number of new cases of a disease that occur during a
specified period of time in a population at risk for developing the disease. Incidence rate
per 1,000=
No. of new cases of a disease occurring in the population during a specified period of
time/No. Of persons who are at risk of developing the disease during that period of time X
1,000. Incidence is a measure of events; measure of risk (transition from non-diseased to
diseased).
Prevalence is defined as the number of affected persons present in the population at a
specific time divided by the number of persons in the population at that time. What
proportion of the population is affected by the disease at that time? No. of cases with
disease/No. Of persons in the population X 1,000. We don’t determine when the disease
developed; just a snapshot of who has it at that time. We can’t account for duration of the
disease.
a. Incidence and prevalence
i. Define
ii. Understand why data are important for measuring risk
iii. Interpret findings
iv. Understand the relationship between incidence and prevalence and impact of each on
duration of disease
Prevalence=Incidence X Duration of Disease
v. Calculate incidence rate
vi. Calculate prevalence rate
vii.Relationship between prevalence, incidence, and mortality
Prevalence and incidence are related by the duration of disease. If incidence is increasing
over time, then duration of illness has to decrease in order to keep the prevalence rate
constant. This may occur through better treatments to cure disease or through higher case-
