This document provides an overview of Epi Info, statistical software developed by the CDC for epidemiology. It discusses the software's history, beginning as an MS-DOS program in 1985. Modern versions are available for Windows, Android, iOS, and as web/cloud apps. The software allows users to create electronic surveys, enter data, and perform analyses including t-tests, regression, and analyses of complex survey data. It has been open source since 2008.

1. Epi Info
Software
BY
Dr. Jitendra Patel
Associate Professor
AIPS, Hyderabad, India.

2. Introduction
• Epi Info is statistical software for epidemiology developed
by Centers for Disease Control and Prevention (CDC)
in Atlanta, Georgia (US).
• Epi Info has been in existence for over 20 years and is
currently available for Microsoft Windows, Android and iOS,
along with a web and cloud version.
• The program allows for electronic survey creation, data
entry, and analysis.
• Within the analysis module, analytic routines include t-tests,
ANOVA, nonparametric statistics, cross tabulations and
stratification with estimates of odds ratios, risk ratios, and
risk differences, logistic regression (conditional and
unconditional), survival analysis (Kaplan Meier and Cox
proportional hazard), and analysis of complex survey data.
• The software is an open-source project with limited support.

3. History
• Epi Info has been in development for over 20 years. The first version, Epi
Info 1, was originally implemented by Jeff Dean as an unpaid intern in high
schoo.
• It was an MS-DOS batch file on 5.25" floppy disks and released in
1985. MS-DOS continued to be the only supported operating system until
the release of Epi Info 2000, which was written in Microsoft's Visual Basic
and became the first Windows-compatible version.
• The last MS-DOS version was Epi Info 6.04d released in January 2001.
• Epi Info 2000 changed the way data was stored by adopting the Microsoft
Access database format, rather than continuing to use the plain-text file
format from the MS-DOS versions.
• Following the release of Epi Info 2000 was Epi Info 2002, then Epi Info
version 3.0, and finally the open-source Epi Info 7. Epi Info 7 was made
open source on November 13, 2008 when its source code was uploaded
to Codeplex for the first time.
• The 7 series is the presently maintained Epi Info product line. Note that
Epi Info 3 for Windows is different from Epi Info 3 for MS-DOS even though
they share the same version number.
• After Microsoft shut down Codeplex in December 2017, the repository of
Epi Info migrated to GitHub.

4. Features
• The most important functions of Epi Info are the ability to rapidly develop a
questionnaire, customize the data entry process, quickly enter data into that
questionnaire, and then analyze the data.
• For epidemiological uses, such as outbreak investigations, being able to rapidly
create an electronic data entry screen and then do immediate analysis on the
collected data can save considerable amounts of time versus using paper surveys.
• Epi Info uses three distinct modules to accomplish these tasks: Form Designer,
Enter, and Analysis.
• Electronic questionnaires are created in the Form Designer module. Individual
questions can be placed anywhere on a page and each form may contain multiple
pages.
• The user defines both the question's prompt and the format of the data that is to
be collected. Data types include numbers, text strings, dates, times, and Boolean.
Users can also create drop-down lists, code tables, and comment legal fields.
• One of the more powerful features of Form Designer is the ability to program
intelligence into a form through a feature called "check code".
• Check code allows for certain events to occur depending on what action a data
entry person has taken.
• For example, if the data entry person types "Male" into a question on gender, any
questions relating to pregnancy might then be hidden or disabled.
• Skip patterns, message boxes, and math operations are also available. Relational
database modeling is supported, as users may link their form to any number of
other forms in their database.

5. • The "Classic Analysis" module is where users
analyze their data. Import and export functions
exist that allow for data to be converted between
plain-text, CSV, Microsoft Excel, Microsoft Access,
MySQL, Microsoft SQL Server, and other formats.
• Many advanced statistical routines are provided,
such as t-tests, ANOVA, nonparametric statistics,
cross tabulations and stratification with estimates
of odds ratios, risk ratios, and risk differences,
logistic regression (conditional and
unconditional), survival analysis (Kaplan Meier
and Cox proportional hazard), and analysis of
complex survey data.

6. • Older versions of Epi Info contained a Report module and a Menu module.
The Report module allowed the user to edit and format the raw output
from other Epi Info modules into presentable documents.
• The menu module allowed for the editing and re-arranging of the basic Epi
Info menu structure.
• This module was powerful enough that several applications have been
built off of it (in versions of Epi Info prior to version 7), including
the National Electronic Telecommunications System for
Surveillance (NETSS) for Epi Info 6.
• Unlike the other modules, the menu module does not have a design-mode
user interface, but instead resides in a .mnu file whose scripts must be
edited manually.
• In Epi Info 7, the Visual Dashboard assumes some of the basic functions of
the report module.
• Epi Info 7 includes a number of nutritional anthropometric functions that
can assist in recording and evaluating measurements of length, stature,
weight, head circumference, and arm circumference for children and
adolescents.
• They can be used to calculate percentiles and number of standard
deviations from the mean (Z-scores) using the CDC/WHO 1978 growth
reference, CDC 2000 growth reference, the WHO Child Growth Reference,
or the WHO Reference 2007.
• It replaces the NutStat and EpiNut modules found in prior versions of Epi
Info.

7. Release history
Series Version Operating
System
Support
Release date Significant changes
Epi Info for DOS
1 MS-DOS
1 Sep 1985
Epi Info for DOS
2 MS-DOS
20 Aug 1986
Epi Info 2000 2000
1.1.2
Windows 9x,
NT 4.0, 2000
2 Nov 2001
First Windows-compatible
version of Epi Info.
Epi Info 3
3.01
Windows 9x,
NT 4.0, 2000,
XP
3 Nov 2003
3.3
Windows 98,
NT 4.0, 2000,
XP
5 Oct 2004
Windows 95 no longer
supported, case-based
mapping functionality added to
the Analysis MAP command
Epi Info 7 7.0.5
(Alpha)
Windows XP,
Vista, 7,
Ubuntu
5 Jan 2009 Programming language
changed to Visual C# .NET;
MySQL and SQL Server
database

8. Thank You