SPSS Programming and Data Management, 4th Edition: A Guide for ...

9Best Practices and Efficiency TipsFigure 2-3Status bar in command syntax window with current line number and column positiondisplayedProtecting the Original DataThe original data file should be protected from modifications that may alter or deleteoriginal variables and/or cases. If the original data are in an external file format (forexample, text, Excel, or database), there is little risk of accidentally overwriting theoriginal data while working in SPSS. However, if the original data are in SPSS-formatdata files (.sav), there are many transformation commands that can modify ordestroy the data, and it is not difficult to inadvertently overwrite the contents of anSPSS-format data file. Overwriting the original data filemayresultinalossofdatathat cannot be retrieved.There are several ways in which you can protect the original data, including:• Storing a copy in a separate location, such as on a CD, that can’t be overwritten.• Using the operating system facilities to change the read-write property of the fileto read-only. If you aren’t familiar with how to do this in the operating system,you can choose Mark File Read Only from the File menu or use the PERMISSIONSsubcommand on the SAVE command.The ideal situation is then to load the original (protected) data file into SPSS and doall data transformations, recoding, and calculations using SPSS. The objective is toendupwithoneormorecommandsyntaxfiles that start from the original data andproduce the required results without any manual intervention.