Itemsets

Magnum Opus finds two forms of pattern: rules and itemsets.  A Magnum Opus itemset is a set of attribute values or items.   The search options enable the user to control the types of itemset that are found.  By default, Magnum Opus finds itemsets that maximize leverage.

A number of measures are listed with each itemset:

Coverage The proportion of examples covered by the itemset.
Leverage The proportion of examples covered by the itemset in excess of the maximum that can be explained by assuming independence between any subsets of the itemset.

Magnum Opus supports two itemset formats.  The detailed format incorporates a brief description of each measure and is recommended for first-time users.   The concise format provides a more concise description of each itemset and is intended for experienced users.

 

© G I WEBB & ASSOCIATES 1999-2005 Last updated September 2005

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