Epidemiologic Field Investigations using Epi Info:

1. Epidemiologic Field Investigationsusing Epi Info:

2. Learning Objectives By the end of this session, you should be able to: Create new variables Recode variables Export data from Epi Info Save your output file Import exported data into other statistical packages

3. What if I want to display the text of RACE instead of numeric codes?

4. Creating Variables The best way to achieve this is to create a new variable that contains the text of race. Define a new variable Recode numeric codes to text; store in new variable Tabulate the new variable

5. DEFINE a new variable

6. Scope of a New Variable Standard: temporary; loses its value and definitions at next READ statement. Standard variables can be assigned values from other variables. Global: exists for duration of the analysis session. Global variables are constant values; cannot be listed. Permanent: has the same value regardless of the record; stored in system registry. Used by application developers to pass values from one program to another.

7. RECODE a variable

8. RECODE Syntax RECODE race TO racetxt 1 = "White" 2 = "Black" 3 = "Hispanic" END

12. Comment Legal Fields Comment Legal Fields are stored as numeric data. FREQ of Comment Legal Fields gives numbers, not text.

13. Check the RECODE

14. How do I create a dummy variable for RACE?

15. DEFINE the variable

16. WHITE: Dummy (Dichotomous) Variable RACE WHITE 1 1 2 3

18. Collapsing Categories using RECODE DEFINE white RECODE race TO white 1 = 1 2 - 3 = 0 END

19. Check the Creation of WHITE

20. How can I re-calculate age at interview?

21. Mathematical Calculations One can calculate age by using either of two methods: ASSIGN and ROUND functions ROUND(DAYS(birthdate,interview)/365.25) YEARS function YEARS(birthdate,interview)

22. Calculating Follow-up Time Similarly, one can calculate the follow-up time in months from follow_up and dateint. Follow-up in months MONTHS(interview, follow_up) Follow-up in days DAYS(interview, follow_up)

25. How do I get data out of Epi Info?

26. WRITE Data into Other Formats One can export data into other formats:

32. ODBC in Stata version 8 By setting up a Data Source Name, you can pull data directly from the mdb file into Stata. Syntax: .odbc load, exec(�SELECT * FROM datatable1�) dsn(�Sample Data�) clear

34. ODBC in R version 1.7.1 By setting up a Data Source Name and installing the RODBC package, you can pull data directly from the mdb file into R. Syntax: # CALL UP THE RODBC LIBRARY library(RODBC) ## TELL R TO MAP IT TO NAMES OF THE DATABASE chnldata <- odbcConnectAccess("c:\\Documents and Settings\\wayne_enanoria\\My Documents\\CIDP\\sampledatabase.mdb") ## LIST THE TABLES IN THE DATABASE sqlTables(chnldata) ## FETCH THE TABLE YOU WANT sampledata <- sqlFetch(channel=chnldata, sqtable="datatable1", rownames = TRUE) ## CLOSE THE CONNECTION odbcClose(chnldata)

36. How do I relate two tables to one another?

37. Example Spreadsheet

39. RELATE Data Tables

42. Combined Table

43. Working With Output By default, output files are stored in the directory of the current project with a prefix followed by a number. For example, �Out16.html�. One can change how and where output files are stored by using the �Storing Output� Command.

44. RouteOut RouteOut command directs output to the named file until the process is terminated by the CloseOut command. The named file is a HTM document where the output is stored. If no directory is specified, the directory of the current project will be used.

45. Summary of Topics Import data from other formats READ (Import) command Create new variables DEFINE and ASSIGN commands Recode variables DEFINE and RECODE commands Export data from Epi Info WRITE command Import exported data into other statistical packages EI -> text file -> other stat programs EI -> other stat programs (ODBC) Save your output file