FISM Procedure

The FISM procedure uses support input to identify the frequent item sets. By default, item sets that contain a maximum of two items are generated. You can specify the item set size in the ITEMS= option.

PROC FISM implements the FP-growth algorithm for finding frequent item sets. PROC FISM discovers the frequent item set by using a support (coverage) measure, which indicates how frequently the items appear in the database. Support of a rule for A and B is expressed as

where X is the number of transactions that contain both A and B, and Y is the total number of transactions.