Association Rules

1
Association Rules

• Transactional data
• Algorithm
• Applications

2
Market Basket Analysis

• Transactional data
• Sparse matrix thousands of columns, each row has
  only dozens of values
• Items
• Itemsets transactions (TID)
• A most cited example diapers and beer

3
Association rule mining

• Finding interesting association or correlation
  relationships
• Defining interesting association rules
• Support (P(AB))
• Confidence (P(BA))
• An association rule
• A -gt B

4
Finding association rules

• Finding frequent itemsets
• downward closure property (or anti-monotonic)
• Finding association rules from frequent itemsets
• Frequent Itemsets
• minisup
• from 1-itemset to k-itemset
• Association rules
• miniconf
• satisfying minimum confidence

5
Apriori

• Level-wise search
• Anti-monotone property
• The procedure
• Join
• prune
• An example

6
Issues

• Efficiency
• Number of association rules
• size of data vs. size of association rules
• Post-processing
• Applications
• combining association rules with classification
• emergency patterns

7
Types of association rules

• Single dimensional association rules
• Multiple dimensional association rules
• Multi-level association rules