Which term describes the rule-based structure used to express associations between items?

• A. Association Rule
• B. Classification Rule
• C. Decision Rule
• D. Heuristic Rule

Answer: (A)

Association rules describe the rule-based structure used to express associations between items. They capture patterns showing how items tend to occur together in transactions, typically written as X -> Y, where X is a set of antecedent items and Y is a set of consequent items. These rules are discovered from data using metrics like support (how often the rule occurs) and confidence (how often Y happens when X happens), making them central to market basket analysis and other co-occurrence discovery tasks. Other terms describe different kinds of rules—for example, classification rules map features to a class label, decision rules guide decisions, and heuristic rules are general problem-solving guidelines. The term that best fits the description of expressing item associations is the association rule.