The id value of the itemset which is the antecedent of the rule. We represent the itemset by the letter A.
The id value of the itemset which is the consequent of the rule. We represent the itemset by the letter C.
The support of the rule, that is, the relative frequency of transactions that contain A and C: support(A->C) = support(A+C)
The confidence of the rule: confidence(A->C) = support(A+C) / support(A)
A very popular measure of interestingness of a rule is lift. Lift values greater than 1.0 indicate that transactions containing A tend to contain C more often than transactions that do not contain A: lift(A->C) = confidence(A->C) / support(C)
Another measure of interestingness is leverage. An association with higher frequency and lower lift may be more interesting than an alternative rule with lower frequency and higher lift. The former can be more important in practice because it applies to more cases. The value is the difference between the observed frequency of A+C and the frequency that would be expected if A and C were independent: leverage(A->C) = support(A->C) - support(A)*support(C)
Also known as Jaccard Similarity, affinity is a measure of the transactions that contain both the antecedent and consequent (intersect) compared to those that contain the antecedent or the consequent (union): affinity(A->C) = support(A+C) / [ support(A) + support(C) - support(A+C)]
An identification to uniquely identify an association rule.
Also known as Jaccard Similarity, affinity is a measure of the transactions that contain both the antecedent and consequent (intersect) compared to those that contain the antecedent or the consequent (union): affinity(A->C) = support(A+C) / [ support(A) + support(C) - support(A+C)]
The id value of the itemset which is the antecedent of the rule.
The id value of the itemset which is the antecedent of the rule. We represent the itemset by the letter A.
The confidence of the rule: confidence(A->C) = support(A+C) / support(A)
The confidence of the rule: confidence(A->C) = support(A+C) / support(A)
The id value of the itemset which is the consequent of the rule.
The id value of the itemset which is the consequent of the rule. We represent the itemset by the letter C.
An identification to uniquely identify an association rule.
Another measure of interestingness is leverage.
Another measure of interestingness is leverage. An association with higher frequency and lower lift may be more interesting than an alternative rule with lower frequency and higher lift. The former can be more important in practice because it applies to more cases. The value is the difference between the observed frequency of A+C and the frequency that would be expected if A and C were independent: leverage(A->C) = support(A->C) - support(A)*support(C)
A very popular measure of interestingness of a rule is lift.
A very popular measure of interestingness of a rule is lift. Lift values greater than 1.0 indicate that transactions containing A tend to contain C more often than transactions that do not contain A: lift(A->C) = confidence(A->C) / support(C)
The support of the rule, that is, the relative frequency of transactions that contain A and C: support(A->C) = support(A+C)
We consider association rules of the form "<antecedent itemset> => <consequent itemset>" next: