Stata Tutorial - Data and Statistical Services - Princeton University

1.3. About Data for StataTo put a data set into Stata’s memory, the data set has to be in a format Stata understands. The following is a list of theextensions of files Stata can read directly.Data Format File Extension Command to read the dataStata .dta . useText (ASCII)Free or fixed columns .raw, .txt . infile usingComma separated values .csv . insheet usingFixed columns .dat . infix usingSAS export .xport, xpt . fdauseMS Access .mdb . odbcMany data download sites provide you with data already formatted for a common statistical program such as Stata, SPSS, orSAS. Formatted data often contain variable labels and value labels, that make it easier for you to understand the contents of thedata.If Stata data are not available, and you can choose a data format between SPSS and SAS, then I would recommend selectingSPSS. You can use SPSS to open SPSS data, then save the data as Stata data. SPSS versions 12 and up can save the data asStata 8 data 1 . Windows version of SPSS is available in McCosh 59 cluster or DSS computer lab. If data are only available inSAS format, you may use SAS to open SAS data, then create SAS export file, as Stata can read a SAS export file. Windowsversion of SAS is available in DSS computer lab. Unix version of SPSS and SAS are available at tombstone.Also, if you acquire data that are in a format other than Stata, you may use DBMS/Copy to convert them into Stata format.Windows version of DBMS/Copy is available in DSS computer lab. Unix version of DBMS/Copy is available at Tombstone.If you have SAS data, we recommend converting them into SAS transport file in SAS instead of using DBMS/Copy.DBMS/Copy has a known issue in converting value labels from SAS to Stata.If formatted data are not available, data distributers may provide set up files in Stata, SPSS, or SAS along with ASCII data.ASCII data set is a text file with rows (or columns) of numbers. If a set up file is available in Stata, you can attach the variableinformation using Stata. If a set up file is available in SPSS, it will be easier to use SPSS to attach the definition, then save thedata as Stata data. If a set up file is available in SAS, you may use SAS to attach the file definition, then create a SAS export filein SAS. You may also modify the set up files in text editors to use in Stata. Commands to define data are different in all threeprograms. If no set up files are available and only PDF codebooks are available, you will need to select the variables you wantto use and create your own set up file for Stata.If you need help in defining or converting data, please come by the Data and Statistical Services computer lab at A-16-H-3 inFirestone Library during walk-in hours or email data@princeton.edu. The hours and directions are available athttp://dss.princeton.edu. If you are emailing questions, please use your Princeton email. Our resources and assistance areavailable to Princeton University community members.Stata data format has changed from version 9 to version 10. Stata 10 can read data saved for Stata 9, but Stata 9 can not readdata saved for Stata 10, while both has the same extension .dta. If you plan to use Stata 9 after using Stata 10, you may save thedata as Stata 9 data in Stata 10. Followinig commands allow you to save data as Stata 9 data in Stata 10.CMD: . saveold filenameMNU: File=> Save As. Then select “Stata 9 Data” from the drop down list for box “Save As Type:”1 Stata 8 and Stata 9 data are interchangeable.Page 5 of 28