Quiz 4 Flashcards
Public Health Surveillance
Where does the word surveillance come from?
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french!
sur (over)
veiller (to watch)
Public Health Surveillance
What is the definition of surveillance?
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close and continuous observation of one or more persons for the purpose of direction, supervision, or control
Public Health Surveillance
What is active surveillance?
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epidemiologist initiated (health department initiated)
Public Health Surveillance
What is passive surveillance?
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physician initiated (health provider initiated)
Public Health Surveillance
What do you do when conducting surveillance?
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- identify, define, and measure the health problem of interest
- collect and compile data about the problem
- analyze and interpret these results
- provide data and interpretation to those responsible for controlling the health problem
- monitor and periodically evaluate the usefulness and quality of surveillance to improve it for future use
Public Health Surveillance
What are the characteristics of surveillance?
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- timeliness: to implement effective control measure
- representation: provide an accurate picture of the temporal trend of the disease
- sensitivity: indentification of individuals with disease
- specificity: exclude those without the disease
Public Health Surveillance
What questions should be considered when selecting a health problem for surveillance?
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- What factors might prompt an investigation into a disease?
- Why would we prioritize one disease over another?
- What characteristics of a disease would warrant action?
Public Health Surveillance
What factors are included when selecting a health problem for surveillance?
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- incidence and prevalence
- severity
- mortality caused by the problem
- socioeconomic impact
- communicability
- potential for an outbreak
- public perception and concern
- international requirements
- preventability, control measures and treatment
- capacity of the health system to implement control measures
Public Health Surveillance
How can you define the health problem?
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by utilizing the case definition for surveillance
Public Health Surveillance
What does the term constellation of signs refer to in disease surveillance?
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situations where a disease is identified based on a group of signs, symptoms, chief complaints, or presumptive diagnoses—rather than specific clinical or lab diagnostic criteria.
ALSO KNOWN AS SYNDROMIC SURVEILLANCE
Public Health Surveillance
What is the goal of syndromic surveillance?
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to provide an earlier indication of an unusual increase in illness
to facilitate early intervention
Public Health Surveillance
Does syndromic surveillance rely on a clinician testing or thinking of a specific disease?
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NO
it is less specific and focuses on syndromes instead of diagnoses
Public Health Surveillance
Once a disease is identified, what data sources must be identified for surveillance?
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- individual persons
- health care providers, facilities and records
- environmental conditions
- administrative actions
- financial transactions (ex: sales of cigs)
- legal actions
- laws and regulations
Public Health Surveillance
What methods can be used to collect majority of health-related data?
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- surveys
- notifications
- registries
- reanalysis
Public Health Surveillance
Define survey
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an investigation that uses a “structured and systematic gather of information” from a sample of “a population of interest to describe the population in quantiative terms”
- most common method for gathering information about populations
- can be conducted once or on a periodic basis
Public Health Surveillance
What must a survey entail?
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- representative sample –> so results can be generalized to the entire population
Public Health Surveillance
Define notification
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the reporting of certain diseases or other health related conditions by a specific group, as specified by law, regulation, or agreement
Public Health Surveillance
What does a notification entail?
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- typically made to the state or local health agency
- when required by law, the diseases are known as notifiable
- initiated by passive surveillance –> providers send reports to a health department
Public Health Surveillance
Define registry
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method for documenting or tracking events or persons over time
they are specifc compared to notifications
because they are intended to be a permanent record of persons or events
Public Health Surveillance
What does a disease registry entail?
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tracks a person with disease over time and usually includes:
- diagnostic
- treatments
- outcome information
Public Health Surveillance
Define reanalysis / secondary use of data
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surveillance for a health problem can use data originally collected for other purposes
Public Health Surveillance
What are some things to keep in mind with reanalysis?
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can lack timeliness or sufficient detail pertinent to current outbreak
however:
primary collection of data is time-consuming and resource-intensive so this may be beneficial when the health problem is of high priority if there are no adequate sources of data
Displaying Public Health Data
What is a table?
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a set of data arranged in rows and columns
Displaying Public Health Data
Why are tables used?
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serve as the basis for preparing additional visual displays of data
simplistic version of recording raw data
Displaying Public Health Data
What is a contingency table?
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a table that consists of two variables and each of those variables have two categories
Displaying Public Health Data
What are composite tables?
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several tables that are combined into one for space conservation on a report
these tables do NOT indicate interrelationship between the variables displayed
Displaying Public Health Data
What are table shells?
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epidemiologists may anticipate and design their analyses in advance to prepare for data collection and expedite data analysis
table can be modified after data collection
Displaying Public Health Data
How can table shells be used?
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to help prepare and makes the data analysis quicker
very important during the planning phase of a study
Displaying Public Health Data
What are class intervals and what are they used for?
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when some variables have broad range of possibility, thus class intervals are created
example:
- 0 drinks / week
- 1-3 drinks / week
- 4-7 drinks / week
- greather than 8 drinks / week
Displaying Public Health Data
What must class intervals entail?
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must be:
- mutually exclusive (each individual falls into one interval)
- exhaustive (ALL individuals can fit into a class interval; some surverys have an option for “other”)
- must have a natural baseline to include those who have not had an exposure (example: for non smokers = 0 cigarettes per day)
Displaying Public Health Data
Define graphs / what do they do?
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display numeric data in visual form
- clearly indentify variables portrayed with legends or keys
- ensure scales for each axis are appropriate for data presented
x-axis = independent variable
y-axis = dependent variable
Displaying Public Health Data
arithmetic-scale line graph
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why use them:
to show patterns or trends over some variable (often time)
when to use:
need to show long series of data (ex: rates over time)
Displaying Public Health Data
semilogarithmic-scale line graph
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why use them:
when the data set is so large
when to use:
proper construction of an arithmetic-scale graph is problematic
Displaying Public Health Data
histograms
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why use them:
to graph the frequency distribution of a continuous variable
Displaying Public Health Data
population pyramid
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when to use / why use:
display the count or percentage of a population by age and sex
Displaying Public Health Data
frequency polygon
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when to use / why use:
to graph a frequency distribution
- numbers of observations in an interval is marked with a single point and each point is connected with a straight line
Displaying Public Health Data
survival curves
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when to use / why use:
display the proportion of one or more groups that are still alive at different time periods
Displaying Public Health Data
scatter diagrams
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when to use / why use:
to portray the relationship between two variables
- a point is placed on the graph where the two variables intersect
Displaying Public Health Data
grouped bar charts
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when to use / why use:
to illustrate data from two or three variable tables
- bars should be illustrated distinctively and described in a legend
Displaying Public Health Data
stacked bar charts
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groups are differentiated within a single bar
cons:
- less effective at displaying the relative size of the subgroups
Displaying Public Health Data
100% component bar charts
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a variant of a stacked bar chart BUT all bars are pulled to the same height and the components are show as % (percentages, not actual values)
Displaying Public Health Data
deviation bar charts
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when to use / why use:
to display both positive and negative changes from a baseline
Displaying Public Health Data
pie charts
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size of the “slices” show the proportional contribution of each component part
Displaying Public Health Data
dot plots
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when to use / why use:
use dots to show the relationship between a categorical and continuous variable
Displaying Public Health Data
phylogenetic tree
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branching chart that indicates the evolutionary lineage or genetic relatedness of organisms
- distance on the tree reflects genetic differences
Displaying Public Health Data
decision trees
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branching chart that represents the logical pathway of a public health decision
building blocks:
- decisions
- outcomes
- probabilities
Displaying Public Health Data
maps
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when to use / why use:
to show geographic location of events or attributes
