Coverage (also called cover or LHS-support) is the support of the
left-hand-side of the rule \(X => Y\), i.e., \(supp(X)\). It represents a measure of
to how often the rule can be applied.
Coverage can be quickly calculated from the rule's quality measures (support and
confidence) stored in the quality slot. If these values are not present,
then the support of the LHS is counted using the data supplied in
transactions.
Coverage is also one of the measures available via the function
interestMeasure()
.