SPSS Categories® 11.0

32 Chapter 3
Categorical Principal Components Discretization
The Discretization dialog box allows you to select a method of recoding your variables.
Fractional-value variables are grouped into seven categories (or into the number of distinct
values of the variable if this number is less than seven) with an approximately normal
distribution, unless specified otherwise. String variables are always converted into
positive integers by assigning category indicators according to ascending alphanumeric
order. Discretization for string variables applies to these integers. Other variables are left
alone by default. The discretized variables are then used in the analysis.
Figure 3.4 Categorical Principal Components Discretization dialog box
Method. Choose between grouping, ranking, and multiplying.
Grouping. Recode into a specified number of categories or recode by interval.
Ranking. The variable is discretized by ranking the cases.
Multiplying. The current values of the variable are standardized, multiplied by 10,
rounded, and have a constant added such that the lowest discretized value is 1.
Grouping. The following options are available when discretizing variables by grouping:
Number of categories. Specify a number of categories and whether the values of the
variable should follow an approximately normal or uniform distribution across those
categories.
Equal intervals. Variables are recoded into categories defined by these equally sized
intervals. You must specify the length of the intervals.