Making Life Easy Using Epi Info:An Introduction

Ali Rowhani-Rahbar, MD, MPH, PhDPostdoctoral ScholarPediatric Infectious Diseases

What is Epi Info?A free public domain software package developed by the Centers for Disease Control and Prevention for the global community of medical and public health professionals. It can be used to rapidly:develop an electronic data entry formenter data into this formanalyze data entered into this form or imported from other software packages

Past, Present, and FutureFirst version: Epi Info 1 (MS-DOS)Released 1985Latest version: Epi Info 3.5.1Released 2008Earlier this year, Epi Info became an open source software. The next version (Epi Info 7) is currently being developed at the CDCs National Center for Public Health Informatics.

Worldwide useA study conducted in 2003 documented at least 1 million downloads in at least 180 countries.Epi Info has been translated to several languages by different institutions and individuals around the world. Examples include:SpanishItalianRussian

Epi Info vs. other software packagesEpi Info has not been designed to replace:Professional data management software packages such as:Microsoft AccessFileMaker Pro Professional data analysis software packages such as:SASStataR

Advantages of Epi InfoFree User-friendly Point-and-clickAll-in-one softwareDesign a data entry form, enter data, and analyze dataTime efficientVery useful for outbreak investigations

Main applications in Epi Info We will discuss these applications today:Make ViewFor designing an electronic data entry form which automatically creates a data tableEnter DataFor entering data into the designed electronic data entry formAnalyze DataFor conducting a relatively wide range of statistical analysis of the data

Other applications in Epi InfoWe will not discuss these applications today:Create Maps (Epi Map)For creating Geographic Information System (GIS) maps and overlaying survey data on to themCreate Reports (Epi Report)For presenting results in a professional formatNutStatA nutrition anthropometry program for calculating BMI and growth Z scores/percentiles

Make View

Make View View is an electronic data entry form that you design based on a questionnaire used for primary data collection.Each view has a corresponding data table in the background. No spreadsheet is involved.There are 17 field (i.e., variable) types that you can choose from (Text, Number, Date, Time, Check Box, Yes/No, Option, etc.)You can also add check codes and skip patterns to your view all by point-and-click.

What is a check code?Check codes are rules and restrictions that you add to your view in order to improve the accuracy or efficiency of the data entry process. Examples include:Making data entry for a particular variable requiredDefining a range for a particular variableMaking a variable Read Only

Create the view here

Define a new field (variable) by right-clicking on the view

Create a skip patternAdd a check code

An example of a skip pattern

An example of a view with fields grouped together and color-codedSource: Epi Info tutorial Rhodococcal Infection After Open-Heart SurgeryBased on a hospital outbreak investigation conducted by an EIS officer. The report was published in the New England Journal of Medicine (New Engl J Med 1991;324:104-9).

Enter Data

Enter DataYou can easily:enter data in the view that you have designedcontrol the order of data entry processnavigate through different recordsfind a particular or a group of records according to a criterion that you define

Analyze Data

Import/Export DataYou can import data generated in some other software packagesText, Excel, dBASE, AccessYou can export data suitable for use in some other software packagesText, Excel, dBASE, Access

Data manipulationYou can perform a relatively wide range of common data manipulation procedures such as:Sorting data on a specific variableRecoding categories of a variableDefining a new variableYou can also merge records in one data table with those in another data table using a key (i.e., common) variable.

Statistical analysis (1)Univariable analysisMeasures of central tendency and dispersionMean, median, mode, quartiles, standard deviation, etc.Bivariable analysisChi-square and Fishers exact testt test and the analysis of variance (ANOVA)Odds ratioRisk ratioRisk difference

Statistical analysis (2)Multivariable analysisLinear regressionLogistic regressionUnconditional and conditionalSurvival analysisKaplan-MeierCox proportional hazard regressionYou can create dummy variables and interaction terms all by point-and-clickComplex sample survey analysis

Analysis OutputProgram EditorCommands Tree

An Example Cross-tabulation of smoking and case/control status

GraphicsTwo Examples

A Kaplan-Meier Survival CurveA Scatterplot

Some Useful Websites

CDC (http://www.cdc.gov/epiinfo)

User forum (http://cms.myepi.info)

North Carolina Center for Public Health Preparedness (Internet-based training)

Thank you!Feel free to send an e-mail with any questions to:rowhani@stanford.edu