DISCRETIZATION Subcommand (CATREG command)

DISCRETIZATION specifies fractional-value variables that you want to discretize. Also, you can use DISCRETIZATION for ranking or for two ways of recoding categorical variables.

• A string variable's values are always converted into positive integers by assigning category indicators according to the ascending alphanumeric order. DISCRETIZATION for string variables applies to these integers.
• When the DISCRETIZATION subcommand is omitted, or when the DISCRETIZATION subcommand is used without a varlist, fractional-value variables are converted into positive integers by grouping them into seven categories (or into the number of distinct values of the variable if this number is less than 7) with a close to normal distribution.
• When no specification is given for variables in a varlist following DISCRETIZATION, these variables are grouped into seven categories with a close-to-normal distribution.
• In CATREG, a system-missing value, user-defined missing values, and values less than 1 are considered to be missing values (see next section). However, in discretizing a variable, values less than 1 are considered to be valid values, and are thus included in the discretization process. System-missing values and user-defined missing values are excluded.

GROUPING. Recode into the specified number of categories.

RANKING. Rank cases. Rank 1 is assigned to the case with the smallest value on the variable.

MULTIPLYING. Multiplying the standardized values (z-scores) of a fractional-value variable by 10, rounding, and adding a value such that the lowest value is 1.