Making Life Easy Using Epi Info: An Introduction

1. Making Life Easy Using Epi Info:An Introduction Ali Rowhani-Rahbar, MD, MPH, PhD Postdoctoral Scholar Pediatric Infectious Diseases

2. 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 form • enter data into this form • analyze data entered into this form or imported from other software packages

3. Past, Present, and Future • First version: Epi Info 1 (MS-DOS) • Released 1985 • Latest version: Epi Info 3.5.1 • Released 2008 • Earlier this year, Epi Info became an “open source” software. • The next version (Epi Info 7) is currently being developed at the CDC’s National Center for Public Health Informatics.

4. Worldwide use • A 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: • Spanish • Italian • Russian

5. Epi Info vs. other software packages • Epi Info has not been designed to replace: • Professional data management software packages such as: • Microsoft Access • FileMaker Pro • Professional data analysis software packages such as: • SAS • Stata • R

6. Advantages of Epi Info • Free • User-friendly • Point-and-click • All-in-one software • Design a data entry form, enter data, and analyze data • Time efficient • Very useful for outbreak investigations

7. Main applications in Epi Info • We will discuss these applications today: • Make View • For designing an electronic data entry form which automatically creates a data table • Enter Data • For entering data into the designed electronic data entry form • Analyze Data • For conducting a relatively wide range of statistical analysis of the data

8. Other applications in Epi Info • We will not discuss these applications today: • Create Maps (Epi Map) • For creating Geographic Information System (GIS) maps and overlaying survey data on to them • Create Reports (Epi Report) • For presenting results in a professional format • NutStat • A nutrition anthropometry program for calculating BMI and growth Z scores/percentiles

9. Make View

10. 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.

11. 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 required • Defining a range for a particular variable • Making a variable “Read Only”

12. Create the view here

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

14. Create a skip pattern Add a check code

15. An example of a skip pattern

16. An example of a view with fields grouped together and color-coded Source: Epi Info tutorial “Rhodococcal Infection After Open-Heart Surgery” Based 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).

18. Enter Data

19. Enter Data • You can easily: • enter data in the view that you have designed • control the order of data entry process • navigate through different records • find a particular or a group of records according to a criterion that you define

21. Analyze Data

22. Import/Export Data • You can import data generated in some other software packages • Text, Excel, dBASE, Access • You can export data suitable for use in some other software packages • Text, Excel, dBASE, Access

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

24. Statistical analysis (1) • Univariable analysis • Measures of central tendency and dispersion • Mean, median, mode, quartiles, standard deviation, etc. • Bivariable analysis • Chi-square and Fisher’s exact test • t test and the analysis of variance (ANOVA) • Odds ratio • Risk ratio • Risk difference

25. Statistical analysis (2) • Multivariable analysis • Linear regression • Logistic regression • Unconditional and conditional • Survival analysis • Kaplan-Meier • Cox proportional hazard regression • You can create dummy variables and interaction terms all by point-and-click • Complex sample survey analysis

26. Analysis Output Commands Tree Program Editor

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

30. Graphics Two Examples

31. A Kaplan-Meier Survival Curve A Scatterplot

32. Some Useful Websites

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

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

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

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