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  • 1. Introduction to Using SPSS Command Files Joel P. Wiesen, Ph.D. jwiesen@appliedpersonnelresearch.com 31th Annual IPMAAC Conference St. Louis, MO June 13, 2007 Wiesen (2007), IPMAAC Conference 1
  • 2. Outline • Overview • Some command syntax details • Examples of command files • Tips • Exercises • Review • Q&A Wiesen (2007), IPMAAC Conference 2
  • 3. Overview • Two ways to use SPSS • Pros and Cons of each type of use • Quick review of SPSS windows • How to write command files • How to save a command file • How to run a command file Wiesen (2007), IPMAAC Conference 3
  • 4. Two Ways to Use SPSS • Drop-down menus – Point-and-click – Widely used – Fraught with problems – Tedious for long analyses • Command syntax files – Not commonly taught in college – Provides more functionality Wiesen (2007), IPMAAC Conference 4
  • 5. Pros and Cons Functionality Menu Command File Re-running Harder Easier Learning curve Easier Harder Debugging Harder Easier Documentation Harder Easier Long analyses Harder Easier All procedures No Yes Wiesen (2007), IPMAAC Conference 5
  • 6. Quick Review of SPSS Windows • Data editor – See data – Transform variables • Output – Results from commands, including tables, charts • Chart editor – Can edit graphs • Syntax editor – Write and execute SPSS commands Wiesen (2007), IPMAAC Conference 6
  • 7. How To Write Command Files • Paste from drop-down menus – Menu choices generate syntax automatically • Modify previous command file • Write commands in text file Wiesen (2007), IPMAAC Conference 7
  • 8. Creating Syntax From Menus • Use drop-down menus but do not run • Choose PASTE – Creates a syntax window • Save command file • Run pasted commands Wiesen (2007), IPMAAC Conference 8
  • 9. How to Save a Command File • File-Save • File extension: .SPS • Can use same name for data and sps files Wiesen (2007), IPMAAC Conference 9
  • 10. How to Run a Command File • Open command file – File-Open – Click on .sps file in Windows Explorer • Highlight all or part of command file • Run commands in one of several ways – Click on right arrow – Control-R – Run-all Wiesen (2007), IPMAAC Conference 10
  • 11. Some Command Syntax Details • What is a command file? • Command syntax structure • Example of an SPSS command • Some details of commands • Common and important commands Wiesen (2007), IPMAAC Conference 11
  • 12. What is a Command File? • An ASCII text file • Contains SPSS commands written out • AKA syntax file Wiesen (2007), IPMAAC Conference 12
  • 13. Command Syntax Structure • Name of command – May include some variable names – May included some command options • Name of subcommand – May include variable names or command options • Slashes used to start subcommands • Can continue over multiple lines • End command with a period or blank line Wiesen (2007), IPMAAC Conference 13
  • 14. Example of an SPSS Command • GET DATA / TYPE=XLS / FILE='c:pathfile_name.xls'. • This is one command – With two subcommands • SPSS tries to use the Excel column heads as the variable names Wiesen (2007), IPMAAC Conference 14
  • 15. Some Details of Commands • Each command begins on a new line • Variable names cannot be abbreviated • Command may span lines • Max line length: 80 characters • Period or blank line terminates command • Command syntax is case insensitive Wiesen (2007), IPMAAC Conference 15
  • 16. Common & Important Commands • Commands allow you to – Get data – Manipulate data – List data – Do statistical analyses – Save data Wiesen (2007), IPMAAC Conference 16
  • 17. Most Important Command • Asterisk • Identifies a comment line • End comment with period or blank line * This is an example of a comment line. * The next two lines correct data errors. Wiesen (2007), IPMAAC Conference 17
  • 18. Compute Command • Used to change values • COMPUTE perscore = (score/60). • COMPUTE composite = var1 + var2 + var3. • COMPUTE average = composite / 3. Wiesen (2007), IPMAAC Conference 18
  • 19. IF • IF (form = "A") zscore = (score – 44.5)/6.5 Wiesen (2007), IPMAAC Conference 19
  • 20. Create Ranks • RANK VARIABLES = written oral ppt (A). • Default is to create new variables – rwritten – roral – rppt • Can specify names of new variables • (A) means ascending Wiesen (2007), IPMAAC Conference 20
  • 21. Save SPSS Data File • SAVE OUTFILE = 'c:pathfilename.sav'. • SAVE OUTFILE = 'c:pathfilename.sav' / DROP ssn. • SAVE OUTFILE = 'c:pathfilename.sav' / KEEP id lastname grade. Wiesen (2007), IPMAAC Conference 21
  • 22. TEMPORARY • TEMPORARY. SELECT IF (eeo_gp = 1). LIST id written oral ppt /CASES = 15. Wiesen (2007), IPMAAC Conference 22
  • 23. SORT • SORT CASES BY grade. • LIST id lastname firstname grade. • SORT CASES BY grade (A). Wiesen (2007), IPMAAC Conference 23
  • 24. Variable Label • VARIABLE LABEL failcol 'failed color vision'. Wiesen (2007), IPMAAC Conference 24
  • 25. Value Label • VALUE LABEL eeo_gp 0 ‘Unknown' 1 'Non-Minority' 2 'Minority' . • VALUE LABEL eeo_gp 0 'Unknown' 1 'Non-Minority' 2 'Minority' . Wiesen (2007), IPMAAC Conference 25
  • 26. Save Non-SPSS Data File • SAVE TRANSLATE OUTFILE = 'c:pathfilename.xls' /TYPE=XLS / KEEP id gender eeo_gp age compos /FIELDNAMES. • This creates an Excel file with variable names for column heads. Wiesen (2007), IPMAAC Conference 26
  • 27. Statistical Commands • Means • Graph • Correlation • Many other commands Wiesen (2007), IPMAAC Conference 27
  • 28. Means Command • MEANS TABLES= oral written BY eeo_gp. – This minimal command will work – Commands have default settings • MEANS TABLES= oral written BY eeo_gp / CELLS MEAN COUNT STDDEV. – This command is more specific. Wiesen (2007), IPMAAC Conference 28
  • 29. Graph • GRAPH /SCATTERPLOT(BIVAR)= oral WITH written /MISSING=LISTWISE /TITLE= 'Title goes here' 'line 2 of title goes here‘ /SUBTITLE= 'sub title goes here‘ /FOOTNOTE= 'footnote goes here‘ 'line 2 footnote goes here'. Wiesen (2007), IPMAAC Conference 29
  • 30. Correlation • CORRELATIONS /VARIABLES= oral written ppt /PRINT=TWOTAIL NOSIG /STATISTICS DESCRIPTIVES /MISSING=PAIRWISE . Wiesen (2007), IPMAAC Conference 30
  • 31. Command File Example • SPSS Program to Grade a Test (See separate pdf file.) Wiesen (2007), IPMAAC Conference 31
  • 32. Tips for Using Command Files • Documenting • Debugging • Use of capitalization • Separate the major aspects of analyses Wiesen (2007), IPMAAC Conference 32
  • 33. Document Your Files • File name • Date created • Author • Log of changes over time • Outline file • Visual divisions of file into sections Wiesen (2007), IPMAAC Conference 33
  • 34. Debugging • Debugging individual commands • Debugging command logic Wiesen (2007), IPMAAC Conference 34
  • 35. Debugging Individual Commands • SPSS is very detail demanding • Look for: – Missing or extra quotation marks – Unbalanced parentheses – Missing periods Wiesen (2007), IPMAAC Conference 35
  • 36. Debugging Command Logic • Look at data at various points in the file – List data – Do crosstabulations • Do analyses in another software package – Excel – SAS – Minitab –R Wiesen (2007), IPMAAC Conference 36
  • 37. Use of Capitalization • Helpful convention – SPSS commands in upper case – Variable names in lower case Wiesen (2007), IPMAAC Conference 37
  • 38. Separate the Major Aspects of Analyses • Read and save – Verify data is read correctly • Groom data – Transform variables • Change numbers 1 to 4 to letters A to D – Add variables • Name of data set • Analyze data Wiesen (2007), IPMAAC Conference 38
  • 39. Name Various Files • Use one basic name – Keep track of all files related to one project • For example: – IPMAAC_2007.dat – Read_IPMAAC_2007.sps – Groom_IPMAAC_2007.sps – Analyze_IPMAAC_2007.sps • Similar system to name output files Wiesen (2007), IPMAAC Conference 39
  • 40. Display Commands in Output • Do this through menu • Edit – Options • Select the Viewer or Draft Viewer tab • Check the Display commands in the log Wiesen (2007), IPMAAC Conference 40
  • 41. SPSS Training Resources • SPSS built-in tutorial – Help-Tutorial-Working with syntax • SPSS help menu – Help - Command Syntax Reference – Full syntax options – Gives examples – States limitations • SPSS website Wiesen (2007), IPMAAC Conference 41
  • 42. SPSS Help • When cursor is in a command – Click Syntax Help button to find out what subcommands and keywords are available for the current command • If the cursor is not in a command – Clicking the Syntax Help button to display an alphabetical list of commands – You can select the one you want. Wiesen (2007), IPMAAC Conference 42
  • 43. Other Training Resources • On line tutorials for SPSS – Many from colleges • Listserves Wiesen (2007), IPMAAC Conference 43
  • 44. Exercise 1 • Fetch data from an Excel file • Get average of oral and written scores • Save data to an SPSS .sav file Wiesen (2007), IPMAAC Conference 44
  • 45. Exercise 2 • Get data from an Excel file • Get average of oral and written z-scores • Save data to an SPSS .sav file Wiesen (2007), IPMAAC Conference 45
  • 46. Review • Pros and cons of drop-down menu • How to use command files Wiesen (2007), IPMAAC Conference 46
  • 47. Drop-Down Menus • Easy to get started • Unwieldy for longer analyses • Easy to make undetected errors • Hard to proof analyses Wiesen (2007), IPMAAC Conference 47
  • 48. How to Use Command Files • Create files • Edit files • Save files • Name files • Run files Wiesen (2007), IPMAAC Conference 48
  • 49. Summary • Start using SPSS drop-down menus • Next, paste menu commands • Write command files as soon as possible • This enables you to – Do longer, more complex analyses – Detect errors and proof analyses Wiesen (2007), IPMAAC Conference 49
  • 50. Final Thoughts • Look at SPSS programs written by others • Become acquainted with SPSS commands • Learn details of commands you use often Copies of this presentation are available at: http://ipmaac.org Wiesen (2007), IPMAAC Conference 50
  • 51. Q&A’s • The floor is open – Questions – Comments Wiesen (2007), IPMAAC Conference 51