Epi Info - Features

Features

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.