User Guide
207
File Handling a
nd Fi le Transformations
How many inde x variables should be in the new file? Index variables can be used as
grouping variables in SPSS procedures. In most cases, a single index variable is
sufficient
; however, if the variable groups in your current file reflect multiple factor
levels, multiple indices may be appropriate.
î‚„ One. The wizard will create a single index variable.
î‚„ More than one. The wizard will create multiple indices and enter the number of
indices tha
t you want to create. The number that you specify affects the next step,
in which the wizard automatically creates the specified number of indices.
î‚„ None. Select this if you do not want to create index variables in the new file.
Example of
One Index for Variables to Cases
In the curr
ent data, there is one variable group, width,andonefactor,time.Widthwas
measured three times and recorded in w1, w2,andw3.
Figure 8-2
3
Current da
ta for one index
We’ll restructure the variable group into a single variable, width, and create a single
numeric index. The new data are shown in the following table.
Figure 8-24
New, restructured data with one ind ex
Index starts with 1 and increments for each variable in the group. It restarts each
time a new row is encountered in the original file. We can now use index in SPSS
procedures that require a grouping variable.