|Developer(s)||Centers for Disease Control and Prevention|
|Stable release||188.8.131.52 / August 9, 2012|
|Written in||Microsoft Visual C# 3.5|
|Type||Statistical software, epidemiology|
Epi Info has been in existence for over 20 years and is currently available for Microsoft Windows. 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 in the public domain, free, and can be downloaded from http://www.cdc.gov/epiinfo. Limited support is available.
An analysis conducted in 2003 documented over 1,000,000 downloads of Epi Info from 180 countries.
Epi Info has been in development for over 20 years. The first version, Epi Info 1, was originally implemented as 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. The 7 series is the presently maintained Epi Info product line. Note that Epi Info 3 for Windows is different than Epi Info 3 for MS-DOS even though they share the same version number.
The next iteration of the Epi Info series, Epi Info 7, was made open source on November 13, 2008 when its source code was uploaded to Codeplex for the first time.
From a user's perspective, one of the most important functions of Epi Info is 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. Other modules include the Report module, a mapping module, a menu module, and various utilities such as StatCalc.
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 is given a high degree of control over the form's appearance and function. 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.
The "Classic Analysis" module is where users analyze their data. Import and export functions exist that allow for file types to be converted between plain-text, CSV, Microsoft Excel, Microsoft Access, dBase, FoxPro, 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.
The "Visual Dashboard" module is a lighter-weight Analysis component that is designed to be easy to use, but does not contain the full set of data management and statistical commands that the "Classic Analysis" module does.
Using the Map module, data can be displayed either by geographic reference or by GPS coordinates. The Report module (planned) allows the user to edit and format output from various Epi Info tools and modules. The resulting HTML document can then be printed or emailed to others.
The menu module (planned) allows for the editing and re-arranging of the basic Epi Info menu structure. This module is 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.
Epi Info 7 also 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.
Future developments 
Version 7 is currently in continuing development as an open-source project and written using Microsoft's C# .NET programming language. Source code distribution and contribution currently takes place through Codeplex. Web-based data entry, reporting capabilities, a fully featured menu module, and handheld/mobile data entry (for Android-based devices) are planned for 2012.
Release history 
|Series||Version||Operating System Support||Support status||Release date||Significant changes|
|Epi Info for DOS||1||MS-DOS||1 Sep 1985|
|2||MS-DOS||20 Aug 1986|
|4.1||MS-DOS||15 Nov 1988|
|5.01||MS-DOS||Oct 1990||Allowed European date formats and non-English characters in data fields.|
|6.0||MS-DOS||1992||Added programmable menu system|
|6.04c||MS-DOS||1998||Year 2000 compatibility upgrade|
|Epi Info 2000||2000 1.1.2||Windows 9x, NT 4.0, 2000||2 Nov 2001||First Windows-compatible version of Epi Info.|
|2002 R2||Windows 9x, NT 4.0, 2000, XP||30 Jan 2003|
|Epi Info 3||3.0||Windows 9x, NT 4.0, 2000, XP||n/a|
|3.01||Windows 9x, NT 4.0, 2000, XP||3 Nov 2003|
|3.2||Windows 9x, NT 4.0, 2000, XP||4 Feb 2004|
|3.2.2||Windows 9x, NT 4.0, 2000, XP||14 Apr 2004|
|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.|
|3.3.2||Windows 98, NT 4.0, 2000, XP||9 Feb 2005|
|3.4||Windows 98, NT 4.0, 2000, XP||30 Apr 2007||Ability to use standard ISO date formats, disallowed multiple instances of the Analysis module, added ability to run reports from Analysis, and CDC flags added to the Nutrition module.|
|3.4.1||Windows 98, NT 4.0, 2000, XP||9 Jul 2007||Added a right-to-left language controller in Analysis|
|3.4.2||Windows 98, NT 4.0, 2000, XP||20 Sep 2007|
|3.4.3||Windows 98, NT 4.0, 2000, XP||17 Oct 2007|
|3.5||Windows 98, NT 4.0, 2000, XP SP3||9 Jun 2008||Added feature to use standardized vocabularies. First version to require Service Pack 3 if running Epi Info on a computer with Windows XP.|
|3.5.1||Windows 98, NT 4.0, 2000, XP SP3, Vista||13 Aug 2008||First version compatible with Windows Vista. This version also fixed compatibility for languages that are read right-to-left.|
|3.5.2||Windows 98, NT 4.0, 2000, XP SP3, Vista, 7||17 Dec 2010||First version compatible with Windows 7. Also included a preview of the new Epi Info 7 MakeView and Enter tools.|
|3.5.3||Windows 98, NT 4.0, 2000, XP SP3, Vista, 7||26 Jan 2011||Minor update to the Epi Info Enter tool released with 3.5.2.|
|3.5.4||Windows 98, NT 4.0, 2000, XP SP3, Vista, 7||10 Aug 2012||Modified installation packaging.|
|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 support added; XML meta-data support added; Linux compatibility added; first Windows version of Epi Info to be open source.|
|184.108.40.206||Windows XP, Vista, 7||27 Sep 2011||Upgraded framework to .NET version 3.5; Added ability to run Epi Info 7 from a flash drive without administrator rights; Added ability for Epi Info 7 forms to work with essentially unlimited number of fields; Mapping module added; Geocoding added; Visual Dashboard module added; plugin-based data driver model added; Linux and MySQL support removed; Growth charting added.|
|220.127.116.11||Windows XP, Vista, 7||28 Oct 2011||Release build. Added ability to install Epi Info 7 using a traditional setup file; Added new check code commands; Added ability to calculate z-scores for the WHO Child Growth Standards and WHO Reference 2007.|
|18.104.22.168||Windows XP, Vista, 7||9 Aug 2012||Major updates to Dashboard module; Added web-based data entry capability; Added features to allow compatibility with the Epi Info for Android app.|
|Series||Version||Operating System Support||Support status||Release date||Significant changes|
See also 
- Quantitative parasitology (free software)
- Epi Map
- Free statistical software
- Epi Info
- Epi Info Community of Users
- Epi Info Community Portal
- Epi Info Community Edition (open source version)