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2004 Public Health Training and Information Network (PHTIN) Series. Site Sign-in Sheet. Please mail or fax your site’s sign-in sheet to: Linda White NC Office of Public Health Preparedness and Response Cooper Building 1902 Mail Service Center Raleigh, NC 27699 - PowerPoint PPT Presentation
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2004 Public Health Training and
Information Network (PHTIN) Series
Site Sign-in Sheet
Please mail or fax your site’s sign-in sheet to:
Linda WhiteNC Office of Public Health Preparedness and ResponseCooper Building1902 Mail Service CenterRaleigh, NC 27699
FAX: (919) 715 - 2246
Outbreak Investigation Methods
From Mystery to Mastery
2004 PHTIN Training Development Team
Pia MacDonald, PhD, MPH - Director, NCCPHP
Jennifer Horney, MPH - Director, Training and Education, NCCPHP
Anjum Hajat, MPH – Epidemiologist, NCCPHP
Penny Padgett, PhD, MPH
Amy Nelson, PhD - Consultant
Sarah Pfau, MPH - Consultant
Amy Sayle, PhD, MPH - Consultant
Michelle Torok, MPH - Doctoral student
Drew Voetsch, MPH - Doctoral Candidate
Aaron Wendelboe, MSPH - Doctoral student
Upcoming PHTIN Sessions
November 9th. . . “Techniques for Review of
Surveillance Data”
December 14th. . . “Risk Communication”
10:00 am - 12:00 pm
(with time for discussion)
Session I – VI Slides
After the airing of each session, NCCPHP will post PHTIN Outbreak Investigation Methods series slides on the following two web sites:
NCCPHP Training web site:http://www.sph.unc.edu/nccphp/phtin/index.htm
North Carolina Division of Public Health, Office of Public Health Preparedness and Response
http://www.epi.state.nc.us/epi/phpr/
Session V
“Analyzing Data”
Today’s Presenters
Michelle Torok, MPH
Graduate Research Assistant and Doctoral Student, NCCPHP
Sarah Pfau, MPH
Consultant, NCCPHP
“Analyzing Data” Learning Objectives
Upon completion of this session, you will:
• Understand what an analytic study contributes to an epidemiological outbreak investigation
• Understand the importance of data cleaning as a part of analysis planning
“Analyzing Data” Learning Objectives
• Know why and how to generate descriptive statistics to assess trends in your data
• Know how to generate and interpret epi curves to assess trends in your outbreak data
• Understand how to interpret measures of central tendency
“Analyzing Data” Learning Objectives (cont’d.)
• Know why and how to generate measures of association for a cohort or case-control study
• Understand how to interpret measures of association (risk ratios, odds ratios) and corresponding confidence intervals
• Know how to generate and interpret selected descriptive and analytic statistics in Epi Info software
Analyzing Data
Overview
Analyzing Data: Session Overview
• Analysis planning• Descriptive epidemiology
– Epi curves– Spot maps– Measures of central tendency – Attack rates
• Analytic epidemiology– Measures of association
• Case study analysis using Epi Info software
Analysis Planning
Analysis Planning
• Regardless of the data analysis software program you use, you will have access to numerous data manipulation and analysis commands
• However, you need to understand the function of each command to determine when and why to use one
Analysis Planning
Several factors influence—and sometimes limit—your approach to data analysis:
– Your research question– Which variables will function as exposure and outcome– Which study design you use– How you select your sample population– How you collect and code information obtained from
study participants
Analysis Planning
Analysis planning can:
– Be an invaluable investment of time– Help you select the most appropriate
epidemiologic methods– Help assure that the work leading up to
analysis yields a database structure and content that your preferred analysis software needs to successfully run analysis programs
Analysis Planning
Three key considerations as you plan your analysis:
1. Work backwards from the research question(s) to design the most efficient data collection instrument
2. Study design will determine which statistical tests and measures of association you evaluate in the analysis output
3. Consider the need to present, graph, or map data
Analysis Planning
1. Work backwards from the research question(s) to design the most efficient data collection instrument
• Develop a sound data collection instrument• Collect pieces of information that can be
counted, sorted, and recoded or stratified• Analysis phase is not the time to realize that
you should have asked questions differently!
Analysis Planning
2. Study design will determine which statistical tools you will use.
• Use risk ratio (RR) with cohort studies and odds ratio (OR) with case-control studies; need to know which to evaluate, because both are generated simultaneously in Epi Info and SAS
• Some sampling methods (e.g., matching in case-controls studies) require special types of analysis
Analysis Planning
3. Consider the need to present, graph, or map data
• Even if you collect continuous data, you may later categorize it so you can generate a bar graph and assess frequency distributions
• If you plan to map data, you may need X-and Y-coordinate or denominator data
Basic Steps of an Outbreak Investigation
1. Verify the diagnosis and confirm the outbreak
2. Define a case and conduct case finding
3. Tabulate and orient data: time, place, person
4. Take immediate control measures
5. Formulate and test hypotheses
6. Plan and execute additional studies
7. Implement and evaluate control measures
8. Communicate findings
Descriptive Epidemiology
Step 3: Tabulate and orient data: time, place, person
Descriptive epidemiology:
•Familiarizes the investigator with the data
•Comprehensively describes the outbreak
•Is essential for hypothesis generation (step #5)
Data Cleaning
• Check for accuracy– Outliers
• Check for completeness– Missing values
• Determine whether or not to create or collapse data categories
• Get to know the basic descriptive findings
Data Cleaning:Outliers
• Outliers can be cases at the very beginning and end that may not appear to be related– First check to make certain they are not due to a
collection, coding or data entry error
• If they are not an error, they may represent– Baseline level of illness– Outbreak source– A case exposed earlier than the others– An unrelated case– A case exposed later than the others– A case with a long incubation period
Data Cleaning:Distribution of Variables
Illness Onset for Outbreak of Gastrointestinal Illness at a Nursing Home
0
2
4
6
8
Day of Onset
Nu
mb
er o
f C
ases
“Outlier”
Data Cleaning:Missing Values
• The investigator can check into missing values that are expected versus those that are due to problems in data collection or entry
• The number of missing values for each variable can also be learned from frequency distributions
Data Cleaning:Frequency Distributions
Data Cleaning:Data Categories
• Which variables are continuous versus categorical?
• Collapse existing categories into fewer?
• Create categories from continuous? (e.g., age)
Descriptive Epidemiology
• Comprehensively describes the outbreak– Time– Place– Person
Descriptive Epidemiology
Time
Descriptive Epidemiology: Time
• Time– Display time trends– Epidemic curves
Descriptive Epidemiology: Time
02468
101214161820
Day
# o
f C
ases
Descriptive Epidemiology:Time
• What is an epidemic curve and how can it help in an outbreak?
– An epidemic curve (epi curve) is a graphical depiction of the number of cases of illness by the date of illness onset
Descriptive Epidemiology:Time
• An epi curve can provide information on the following characteristics of an outbreak:
– Pattern of spread– Magnitude– Outliers– Time trend– Exposure and / or disease incubation period
Epidemic Curves
Patterns of Spread
Epidemic Curves
• The overall shape of the epi curve can reveal the type of outbreak
– Common source• Intermittent• Continuous• Point source
– Propagated
Epidemic Curves:Common Source
• People are exposed to a common harmful source
• Period of exposure may be brief (point source), long (continuous) or intermittent
Epi Curve: Common Source Outbreak with Intermittent Exposure
Epi Curve: Common Source Outbreak with Continuous Exposure
Epi Curve: Point Source Outbreak
Epi Curve: Propagated Outbreak
Epidemic Curves
Outbreak Magnitude
Epidemic Curves
Epidemic Curves
Outbreak Time Trend
Epidemic Curves
Provide information about the time trend of the outbreak
• Consider:– Date of illness onset for the first case– Date when the outbreak peaked – Date of illness onset for the last case
Epidemic Curves
Epidemic Curves
Period of Exposure / Incubation Period
Epidemic Curves
• If the timing of the exposure is known, epi curves can be used to estimate the incubation period of the disease
• The time between the exposure and the peak of the epi curve represents the median incubation period
Epidemic Curves
• In common source outbreaks with known incubation periods, epi curves can help determine the average period of exposure
– Find the average incubation period for the organism and count backwards from the peak case on the epi curve
Epidemic Curves
• This can also be done to find the minimum incubation period
– Find the minimum incubation period for the organism and count backwards from the earliest case on the epi curve
Exposure / Outbreak Incubation Period
• Average and minimum incubation periods should be close and should represent the probable period of exposure
• Widen the estimated exposure period by 10% to 20%
Onset of illness among cases of E. coli O157:H7 Infection, Massachusetts, December, 1998.
Onset of illness among cases of E. coli O157:H7 Infection, Massachusetts, December, 1998.
Calculating Incubation Period
Epidemic Curves
Creating an Epidemic Curve
Creating an Epidemic Curve
Provide a descriptive titleLabel each axisPlot the number of cases of disease
reported during an outbreak on the y-axisPlot the time or date of illness onset on the
x-axisInclude the pre-epidemic period to show
the baseline number of cases
Epi Curve for a Common Source Outbreak with Continuous Exposure
Y-
Axi
s
X - Axis
Creating an Epidemic CurveX-axis considerations
Choice of time unit for x-axis depends upon the incubation period
• Begin with a unit approximately one quarter the length of the incubation period
Example: 1. Mean incubation period for influenza = 36 hours2. 36 x ¼ = 93. Use 9-hour intervals on the x-axis for an outbreak
of influenza lasting several days
Creating an Epidemic Curve
X-axis considerations
• If the incubation period is not known, graph several epi curves with different time units
• Usually the day of illness onset is the best unit for the x-axis
Epi Curve X-Axis Considerations
05
101520253035404550
10/1-10/7 10/8-10/14 10/15-10/21 10/22-10/28
Week of Onset
# o
f C
ases
0123456789
10
10/2
/200
2
10/4
/200
2
10/6
/200
2
10/8
/200
2
10/1
0/20
02
10/1
2/20
02
10/1
4/20
02
10/1
6/20
02
10/1
8/20
02
10/2
0/20
02
10/2
2/20
02
10/2
4/20
02
10/2
6/20
02
10/2
8/20
02
10/3
0/20
02
Day of Onset#
of
Cas
es
X-axis unit of time = 1 week X-axis unit of time = 1 day
Descriptive Epidemiology
Place
Descriptive Epidemiology: Place
• Provides information on the geographic boundaries of the outbreak
• May highlight outbreak patterns
Descriptive Epidemiology: Place
• Spot map
– Shows where cases live, work, spend time
– If population size varies between locations being compared, use location-specific attack rates instead of number of cases
Descriptive Epidemiology: Place
Source: http://www.phppo.cdc.gov/PHTN/catalog/pdf-file/LESSON4.pdf
Descriptive Epidemiology
Person
Descriptive Epidemiology: Person
• Data summarization for descriptive epidemiology of the population– Line listings– Graphs
• Bar graphs• Histograms
Line Listing Signs/
SymptomsLab Demograph
ics
Case #
Report Date
Onset Date
Physician
Diagnosis
N V J HAIgM
Sex
Age
1 10/12/02 10/5/02 Hepatitis A
1 1 1 1 M 37
2 10/12/02 10/4/02 Hepatitis A
1 0 1 1 M 62
3 10/13/02 10/4/02 Hepatitis A
1 0 1 1 M 38
4 10/13/02 10/9/02 NA 0 0 0 NA F 44
5 10/15/02 10/13/02 Hepatitis A
1 1 0 1 M 17
6 10/16/02 10/6/02 Hepatitis A
0 0 1 1 F 43
Bar Graph
Histogram
Epidemic Curve for Outbreak of Gastrointestinal Illness in a Nursing Home, 2002
5 minute break
Descriptive Epidemiology
Measures of Central Tendency
Descriptive Epidemiology
– Measures of central tendency• Mean• Median• Mode• Range
Measures of Central Tendency
Mean (Average)The sum of all values divided by the number of values
Example:
1.Cases 7,10, 8, 5, 5, 37, 9 years old
2.Mean = (7+10+8+5+5+37+9)/7
3.Mean = 11.6 years of age
Measures of Central Tendency
Median (50th percentile)
The value that falls in the middle position when the measurements are ordered from smallest to largest
Example:
1.Ages 7,10, 8, 5, 5, 37, 9
2.Ages sorted: 5, 5, 7, 8, 9,10, 37
3.Median age = 8
Calculate a Median ValueIf the number of measurements is odd:
Median = value with rank (n+1) / 2• 5, 5, 7, 8, 9,10, 37 • n = 7, (n+1) / 2 = (7+1) / 2 = 4• The 4th value = 8
Where n = the number of values
Calculate a Median Value
If the number of measurements is even:
Median=average of the two values with a.rank of n / 2 and b.(n / 2) + 1Where n = the number of values
• 5, 5, 7, 8, 9,10, 37 • n = 7; (7 / 2) = 3.5. So “8” is the first value• (7 / 2) + 1 = 4.5, so “9” is the second value• (8 + 9) / 2 = 8.5• The Median value = 8.5
Measures of Central TendencyMode [Modal Value]
• The value that occurs the most frequently– Example: 5, 5, 7, 8, 9,10, 37
Mode= 5
• It is possible to have more than one mode– Example: 5, 5, 7,8,10,10, 37
Modes= 5 and 10
Measures of Central Tendency
Mode [Modal Value]:
The value for the variable in which the greatest frequency of records fall
Epi Info limitation: If multiple values share the same frequency that is also the highest frequency, Epi Info will identify only the first value it encounters as “Mode” as it scans the table in ascending order
Measures of Central Tendency Mode Software Limitation
The ages 11, 17, 35, and 62 all qualify for the status of “mode,” but Epi Info identifiesAge 11 as the mode in analysis output for MEANS AGE in viewOswego.
Modal Values
Measures of Central Tendency
3 7711 36.836.0Min MaxMode
50th percentile
Median Mean(average)
Activity:Calculate Mean and Median
Completion time: 5 minutes
Calculate Mean and Median AgeCase # Age (Years)1 5
2 9
3 7
4 6
5 8
6 5
For an even number of measurements, Median = the average of two values ranked:
a. N / 2b. (n / 2) + 1
Calculate Mean and Median Age
Mean age:• 5+9+7+6+8+5=40• 40 / 6 = 6.67 years
Median age:• 5,5,6,7,8,9• Average of values ranked (n/2) and (n/2)+1• =(6/2) and (6/2) +1 = average of 6 and 7• =(6+7) / 2 = 6.5 years
Attack Rates
Attack Rates (AR)AR
# of cases of a disease
# of people at risk (for a limited period of time)
Food-specific AR# people who ate a food and became ill
# people who ate that food
Food-Specific Attack Rates
CDC. Outbreak of foodborne streptococcal disease. MMWR 23:365, 1974.
Consumed
ItemDid Not Consume
Item
Item Ill Total AR(%) Ill Total AR(%)
Chicken 12 46 26 17 29 59
Cake 26 43 61 20 32 63
Water 10 24 42 33 51 65
Green Salad 42 54 78 3 21 14
Asparagus 4 6 67 42 69 61
Stratified Attack Rates
Ill Well Total AR(%)
Women 13 16 29 45
Men 5 27 32 16
Attack rate in women: 13 / 29 = 45%
Attack rate in men: 5 / 32 = 16%
Question & Answer Opportunity
Hypothesis Generation vs. Hypothesis Testing
Hypothesis Generation vs. Hypothesis Testing
Step 5a. Formulate hypotheses– Occurs after having spoken with some case –
patients and public health officials – Based on information form literature review– Based on descriptive epidemiology (step #3)
Step 5b. Test hypotheses– Occurs after hypotheses have been generated– Based on analytic epidemiology
Descriptive Epidemiology
Analytic Epidemiology
Search for clues Clues available
Formulate hypotheses Test hypotheses
No comparison group Comparison group
Answers: How much, who, what, when, where
Answers: How, why
5 minute break
Analytic Epidemiology
Analytic Epidemiology
• Measures of Association– Risk Ratio (cohort study)– Odds Ratio (case-control study)
Cohort versus Case-Control Study
Cohort versus Case-Control Study
Cohort Study
Measure of Association
Risk Ratio
Risk Ratio
Ill Not Ill Total
Exposed A B A+B
Unexposed C D C+D
Risk Ratio [A/(A+B)]
[C/(C+D)]
Risk Ratio Example
Ill Well Total
Ate alfalfa sprouts 43 11 54
Did not eat alfalfa sprouts
3 18 21
Total 46 29 75
RR = (43 / 54) / (3 / 21) = 5.6
Interpreting a Risk Ratio
• RR=1.0 = no association between exposure and disease
• RR>1.0 = positive association
• RR<1.0 = negative association
Case-Control Study
Measure of Association
Odds Ratio
Odds Ratio
Cases Controls
Exposed A B
Unexposed C D
Odds Ratio (A/C)/(B/D)=(A*D)/(B*C)
Odds Ratio Example
Case Control Total
Ate at restaurant X 60 25 85
Did not eat at restaurant X
18 55 73
Total 78 80 158
OR = (60 / 18) / (25 / 55) = 7.3
Interpreting an Odds Ratio
The odds ratio is interpreted in the same way as a risk ratio:
• OR=1.0 = no association between exposure and disease
• OR>1.0 = positive association
• OR<1.0 = negative association
What to do with a Zero CellCase Control Total
Ate at restaurant X 60 0 60
Did not eat at restaurant X
18 55 73
Total 78 55 133
•Try to recruit more study participants
•Add 1 to each cell*
*Remember to document / report this!
Confidence Intervals
Confidence Intervals• Allow the investigator to:
– Evaluate statistical significance
– Assess the precision of the estimate (the odds ratio or risk ratio)
• Consist of a lower bound and an upper bound
– Example: RR=1.9, 95% CI: 1.1-3.1
Confidence Intervals• Provide information on precision of
estimate
– Narrow confidence intervals =more precise
– Wide confidence intervals =less precise
• Example: OR=10, 95% CI: 0.9 - 44.0
• Example: OR=10, 95% CI: 9.0 - 11.0
Analysis Output
Step 6: Plan and Execute Additional Studies
• To gather more specific info– Example: Salmonella muenchen
• Interventional study – Example: implement intensive hand-washing
Question & Answer Opportunity
Epi Info Analysis
Case Study
Download Epi Info software for free at:
http://www.cdc.gov/epiinfo
Case Study Overview
• Oswego County, New York: 1940
• 80 people attended a church supper on 4/18
• 46 people who attended the supper suffered from gastrointestinal illness beginning 4/18 and ending 4/19
• 75 people (ill and non-ill) interviewed
• Investigation focus: church supper as source of infection
Church Supper Menu
Case Study
Descriptive Epidemiology
Case Study
• Investigators needed to determine:
a) The type of outbreak occurring;
b) The pathogen causing the acute gastrointestinal illness; and
c) The source of infection
Data Cleaning
Know your data! Know the:
• Number of records• Field formats and contents• Special properties• Table relationships
Data Cleaning
Tell Epi Info which records to include in analyses
Case Study: Line Listing
• Organize and review data about time, person, and place that were collected via hypothesis generating interviews.
Epi Info Demonstration
•Display Variables•Line Listing•Means
Case Study: Line Listing
DO try this at home!
Case Study: Means
Case Study: Frequency Distributions
• Gender
• Age
Epi Info Demonstration
•Frequency Table•Recode data•Graph data
Frequency by Gender
Frequency by AGE Category
AGE Distribution among Cases
Case Study:Epidemic Curve
Variable of Interest:
DATEONSET (date of onset of illness)
– Entered into database in mm/dd/yyyy/hh/mm/ss/AM PM field format
Case Study: Epidemic Curve
Point-Source Outbreak
‘Textbook’ distributionCase Study distribution
Case Study: Epidemic Curve
Maximum incubation period
Overlap
Average incubation period
Using Epi Info to Create Epi Curves
To create an epi curve with Epi Info1. Open the “Analyze data” component
2. Use the Read command to use the outbreak data
3. Click on the “Graph” command
4. Choose “Histogram” as the “Graph Type”
5. Choose date / time of illness onset variable as the x- axis main variable
Using Epi Info to Create Epi Curves
To create an epi curve with Epi Info:6. Choose “count” from the “Show value of”
option beneath the y-axis option
7. Choose weeks, days, hours, or minutes for the x-axis interval from the “interval” dropdown menu
8. Type in graph title where it says “Page title”
9. Click “OK”
Determine Incubation Period
Create a temporary variable called “Incubation” in Analyze Data:
INCUBATION = DATEONSET – TIMESUPPER
Where field format is identical:
Date / time – mm/dd/yyyy/hh/mm/ss/AM PM
Mean Incubation
Calculate Mean Incubationin Epi Info
Identify the Pathogen. . .
Potential Enteric Agents
Viruses Bacteria Parasites Toxins
Norwalk CampylobacterCyrptospor-idium parvum
Clostridium botulinum
Norwalk-like viruses (caliciviruses)
E. coli CyclosporaStaph. aureus
RotavirusSalmonella spp.
GiardiaMushroom toxins
Hepatitis A ShigellaEntamoeba histolytica
Fish/Shellfish toxins
Pathogen IdentificationResource
CDC’s Foodborne Outbreak Response and Surveillance Unit
“Guide to Confirming the Diagnosis in Foodborne Diseases”
http://www.cdc.gov/foodborneoutbreaks/guide_fd.htm
Verify the Diagnosis: Find Plausible Agents
Evaluate:
predominant signs and symptoms
incubation period
duration of symptoms
suspected food
laboratory testing of stool, blood, or vomitus
Case Study:Attack Rates
Obtain the information that you need to calculate food-specific attack rates via:
A. Stratified Frequency TablesB. Line Listings
Food-specific AR# people who ate a food and became ill
# people who ate that food
Stratified Frequency Tables
AR for people who consumed cake: 27 / 40 = 67.5%
40 people ate cake; 27 people who ate cake are ill.
AR for people who did not consume cake:
19 / 35 = 54.2%
35 people did not eat cake;19 of those people are ill.
Line Listings
13 + 27 people ate cakes
27 people who ate cake are ill
AR for people whoConsumed cake: 27 / 40 = 67.5%
Case Study Attack Rates Consumed
ItemDid Not Consume
Item
Item Ill Total AR(%) Ill Total AR(%)
Baked Ham 29 46 63% 17 29 59%
CabbageSalad
18 28 64% 28 47 60%
Cakes 27 40 68% 19 35 54%
Chocolate Ice Cream
25 47 53% 20 27 74%
VanillaIce Cream
43 54 80% 3 21 14%
Generate and Testa Hypothesis!
Generate and Test a Hypothesis!
• The epi curve is indicative of a Point-Source outbreak
• Based on the incubation period, we suspect Staphylococcus aureus as the pathogen
• The food-specific attack rates lead us to believe that vanilla ice cream may be the source of infection
Case Study
Analytic Epidemiology
Case Study
Epi Info Demonstration
Tables command
Tables Analysis Output
2 x 2 Table Shell Epi Info 2 x 2 Table
Tables Analysis Output
“The risk of becoming ill was more than five times greater for peoplewho consumed vanilla ice cream than for
people who did not consume vanilla ice cream.”
Case StudyAnalytic Results
- Point-Source Outbreak
- Staphylococcus aureus is suspected pathogen based on 4.3 hour average incubation period
- Vanilla ice cream as suspected source of infection (highest food-specific AR of 80%)
- Vanilla ice cream RR = 5.6
- Vanilla ice cream C.I. = 1.9 – 16.0
Question & AnswerOpportunity
Session V Summary
Analysis planning can: be an invaluable investment of time; help you select the most appropriate epidemiologic methods; and help assure that the work leading up to analysis yields a database structure and content that your preferred analysis software needs to successfully run analysis programs.
As you plan your analysis: 1) Work backwards from the research question(s) to design the most efficient data collection instrument; 2) Consider your study design to guide which statistical tests and measures of association you evaluate in the analysis output; and 3) Consider the need to present, graph, or map data
Session V SummaryDescriptive epidemiology: 1) Familiarizes the investigator with data about time, place, and person; 2) Comprehensively describes the outbreak; and 3) Is essential for hypothesis generation.
Data cleaning is the first step in preparing to generate descriptive statistics, as it contributes to the accuracy and completeness of the data.
Measures of central tendency provide a means of assessing the distribution of data. Measures include mean, median, mode, and range.
Epi curves, spot maps, and line listings are all ways in which you can generate and review the time, place, and person elements – respectively – of descriptive statistics.
Session V Summary
Attack rates are descriptive statistics that are useful for comparing the risk of disease in groups with different exposures (e.g., consumption of individual food items).
Analytic epidemiology allows you to test the hypotheses generated via review of descriptive statistics and the medical literature.
The measures of association for case control and cohort analytic studies, respectively, are odds ratios and risk ratios.
Confidence intervals that accompany measures of association evaluate the statistical significance of the measures and assess the
precision of the estimates.
Next Session November 9th10:00 a.m. - Noon
Topic: “Techniques for Review of Surveillance Data”
Session V Slides
Following this program, please visit one of the web sites below to access and download a copy of today’s slides:
NCCPHP Training web site:http://www.sph.unc.edu/nccphp/phtin/index.htm
North Carolina Division of Public Health, Office of Public Health Preparedness and Response
http://www.epi.state.nc.us/epi/phpr/
Site Sign-in Sheet
Please mail or fax your site’s sign-in sheet to:
Linda WhiteNC Office of Public Health Preparedness and ResponseCooper Building1902 Mail Service CenterRaleigh, NC 27699
FAX: (919) 715 - 2246
References and ResourcesCenters for Disease Control and Prevention (1992).
Principles of Epidemiology, 2nd ed. Atlanta, GA: Public Health Practice Program Office.
Division of Public Health Surveillance and Informatics, Epidemiology Program Office, Centers for Disease Control and Prevention (January 2003). Epi Info Support Manual. [included with installation of the software, which can be found at: http://www.cdc.gov/epiinfo/index.htm]
Gordis L. (1996). Epidemiology. Philadelphia, WB Saunders.
References and Resources
Rothman KJ. Epidemiology: An Introduction. New York, Oxford University Press, 2002.
Stehr-Green, J. and Stehr-Green, P. (2004). Hypothesis Generating Interviews. Module 3 of a Field Epidemiology Methods course being developed in the NC Center for Public Health Preparedness, UNC Chapel Hill.
Torok, M. (2004). FOCUS on Field Epidemiology. “Epidemic Curves”. Volume 1, Issue 5. NC Center for Public Health Preparedness