Tips for working with syntax

in IBM SPSS Statistics

• Use the paste button on any

dialog box

• Record commands in the log

Edit –> Options –> Viewer

• Retrieve commands from the

journal file - statistics.jnl.

Edit –> Options –> File Locations

• Auto-complete in the syntax

editor and build commands

interactively

How to create a syntax file

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• Highlight the commands you want to run in a command syntax window

• Invoke one command file from another using the INCLUDE or INSERT command

• Use the production facility to run syntax files

• Use the Statistics Batch Facility (Statistics Server)

Running commands in a syntax file

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•Utilities -> Production Facility

It is often necessary to recode or modify original variables

Best practise is to assign the modified values to new

variables and keep the original variables unchanged

Creating a new variable allows you to compare the initial and

the modified values to verify the recode/modification has

been done correctly

Do not Overwrite Original Variables

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Instead of overwriting the variable always create a new one

• COMPUTE var1=var1*2

• COMPUTE var1_new=var1*2

• RECODE var2 (1 thru5=1)(6 thru 10 = 2)

• RECODE var2 (1 thru5=1)(6 thru 10 = 2)(ELSE=COPY) /INTO var2_new

Overwriting Variables in Syntax

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For transformations that require intermediate variables

temporary (or scratch) variables can be used

Any variable name that begins with a # is treated as a

temporary variable

These variables are discarded at the end of a series of

transformations when SPSS encounters an EXECUTE

command or other commands that read the data

Using Temporary Variables

6

This example syntax creates a variable called var1 and then

computes the factorial (n!)

DATA LIST FREE / var1.

BEGIN DATA

1 2 3 4 5

END DATA.

COMPUTE factor=1.

LOOP #tempvar=1 TO var1.

-COMPUTE factor=factor * #tempvar.

END LOOP.

EXECUTE.

A temporary variable tempvar is used to do the calculation: n*(n-

1)*(n-2)*(n-3) * ...*1

This is done within a LOOP – END LOOP structure

Example using Temporary variables

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SPSS is designed to minimise the number of times it has to

read the data, however each time an EXECUTE command is

executed through syntax the data is read.

Statistical and Charting procedures always read the data but

most transformation commands do not require a separate

data pass

Creating command syntax from pasting different procedures

can include a lot of extra EXECUTE commands which can

increase processing time

Use EXECUTE sparingly

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In most cases virtually all of the auto-generated EXECUTE

commands can be removed, and this will speed up

processing

To turn off the automatic, immediate execution of

transformations and the associated pasting of EXECUTE

commands:

Edit -> Options -> Data tab: Calculate values before used.

Use EXECUTE sparingly

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Instead of working with very large syntax files with 1000’s of

lines of code, break down your syntax file into a number of

standalone files

You might have a syntax separate file for:

• Preparing and standardising data

• Merging data files

• Performing tests on data

• Running reports

Using the INSERT command and a master command file

that specifies all of the other command files you can partition

all your tasks into separate command files

Using the INSERT command

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The INSERT command provides a method for linking

multiple syntax files together making it possible to reuse

blocks of command syntax

Using the INSERT command

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