NR 503 MIDTERM STUDY GUIDE (VERSION 1)
1. Understand and compare the different measures of morbidity
a. Incidence and prevalence
i. Define
A prevalence rate is the proportion of the population that has a
health condition at a point in time. For example, 70 influenza
case-patients in March 2005 reported in County A.
Incidence rate or person-time rate is a measure of incidence that
incorporates time directly into the denominator. Incidence
refers to the occurrence of new cases of disease or injury in a
population over a specified period of time. Although
some epidemiologists use incidence to mean the number of new
cases in a community, others use incidence to mean the number
of
new cases per unit of population.
ii. Understand why data are important for measuring risk
iii. Interpret findings
Interpretation involves putting the study findings into
perspective, identifying the key take-home messages, and
making sound recommendations. Doing so requires that the
epidemiologist be knowledgeable about the subject matter and
the strengths and weaknesses of the study
iv. Understand the relationship between incidence and prevalence
and impact of each on duration of disease
The two primary measures of morbidity are incidence and
prevalence.
• Incidence rates reflect the occurrence of new disease in a
population. An incidence rate describes how quickly disease
occurs in a population.
• Prevalence reflects the presence of disease in a population.
v. Calculate incidence rate
Number of new cases of disease or injury during specified period
Time each person was observed, totaled for all persons
vi. Calculate prevalence rate
Number of new cases of disease or injury during specified
period
Time each person was observed, totaled for all persons
vii. Relationship between prevalence, incidence, and mortality
Incidence, prevalence, and mortality rates are three frequency
measures that are used to characterize the occurrence of health
events in a population.
1
, Incidence rate or person-time rate is a measure of incidence that
incorporates time directly into the denominator. A prevalence
rate is the
proportion of the population that has a health condition at a
point
in time. A mortality rate is a measure of the frequency of
occurrence of
death in a defined population during a specified interval.
viii. Examples of incidence rates and prevalence rates
Prevalence example, 70 influenza case-patients in March 2005
reported in County A,
Incidence for example, 70 new cases of breast cancer per 1,000
women per year. This measure conveys a sense of the speed
with which disease occurs in a population, and seems to imply
that this pattern has occurred and will continue to occur for the
foreseeable future.
2. Surveillance
a. Importance of surveillance
Public health surveillance is the ongoing, systematic collection,
analysis, interpretation, and dissemination of health data to help guide
public health decision making and action. Surveillance is equivalent to
monitoring the pulse of the community. The purpose of public health
surveillance, which is sometimes called “information for action,”18 is
to portray the ongoing patterns of disease occurrence and disease
potential so that investigation, control, and prevention measures can
be applied efficiently and effectively
b. Define and discuss passive verses active surveillance, including
examples and advantages and disadvantages of each
surveillance, passive public health surveillance in which data are sent
to the health agency
without prompting. form of data collection, in which health-care
providers send
reports to a health department on the basis of a known set of rules
and regulations, is called passive surveillance (provider-initiated).
Investigators may conduct what is sometimes called stimulated or
enhanced passive surveillance by sending a letter describing the
situation and asking for reports of similar cases
surveillance, active public health surveillance in which the health
agency solicits reports. This active surveillance (health department-
initiated) is usually limited to specific diseases over a limited period
2
1. Understand and compare the different measures of morbidity
a. Incidence and prevalence
i. Define
A prevalence rate is the proportion of the population that has a
health condition at a point in time. For example, 70 influenza
case-patients in March 2005 reported in County A.
Incidence rate or person-time rate is a measure of incidence that
incorporates time directly into the denominator. Incidence
refers to the occurrence of new cases of disease or injury in a
population over a specified period of time. Although
some epidemiologists use incidence to mean the number of new
cases in a community, others use incidence to mean the number
of
new cases per unit of population.
ii. Understand why data are important for measuring risk
iii. Interpret findings
Interpretation involves putting the study findings into
perspective, identifying the key take-home messages, and
making sound recommendations. Doing so requires that the
epidemiologist be knowledgeable about the subject matter and
the strengths and weaknesses of the study
iv. Understand the relationship between incidence and prevalence
and impact of each on duration of disease
The two primary measures of morbidity are incidence and
prevalence.
• Incidence rates reflect the occurrence of new disease in a
population. An incidence rate describes how quickly disease
occurs in a population.
• Prevalence reflects the presence of disease in a population.
v. Calculate incidence rate
Number of new cases of disease or injury during specified period
Time each person was observed, totaled for all persons
vi. Calculate prevalence rate
Number of new cases of disease or injury during specified
period
Time each person was observed, totaled for all persons
vii. Relationship between prevalence, incidence, and mortality
Incidence, prevalence, and mortality rates are three frequency
measures that are used to characterize the occurrence of health
events in a population.
1
, Incidence rate or person-time rate is a measure of incidence that
incorporates time directly into the denominator. A prevalence
rate is the
proportion of the population that has a health condition at a
point
in time. A mortality rate is a measure of the frequency of
occurrence of
death in a defined population during a specified interval.
viii. Examples of incidence rates and prevalence rates
Prevalence example, 70 influenza case-patients in March 2005
reported in County A,
Incidence for example, 70 new cases of breast cancer per 1,000
women per year. This measure conveys a sense of the speed
with which disease occurs in a population, and seems to imply
that this pattern has occurred and will continue to occur for the
foreseeable future.
2. Surveillance
a. Importance of surveillance
Public health surveillance is the ongoing, systematic collection,
analysis, interpretation, and dissemination of health data to help guide
public health decision making and action. Surveillance is equivalent to
monitoring the pulse of the community. The purpose of public health
surveillance, which is sometimes called “information for action,”18 is
to portray the ongoing patterns of disease occurrence and disease
potential so that investigation, control, and prevention measures can
be applied efficiently and effectively
b. Define and discuss passive verses active surveillance, including
examples and advantages and disadvantages of each
surveillance, passive public health surveillance in which data are sent
to the health agency
without prompting. form of data collection, in which health-care
providers send
reports to a health department on the basis of a known set of rules
and regulations, is called passive surveillance (provider-initiated).
Investigators may conduct what is sometimes called stimulated or
enhanced passive surveillance by sending a letter describing the
situation and asking for reports of similar cases
surveillance, active public health surveillance in which the health
agency solicits reports. This active surveillance (health department-
initiated) is usually limited to specific diseases over a limited period
2
