Decision Table

Definition

A Decision Table is a structured matrix that maps combinations of conditions to their corresponding actions or outcomes. Each column represents a unique rule, listing the condition values that must be true for a specific outcome to occur. Decision tables make complex conditional logic explicit, complete, and easy to validate.

Inputs

• A set of business rules or conditional logic to be documented
• All relevant conditions (variables) and the possible values each can take

Outputs

• A matrix listing every condition combination and its resulting action, ensuring complete coverage of logic paths
• A validated, unambiguous reference for both business stakeholders and developers

When to Use

• Business rules involve multiple conditions interacting (e.g. eligibility rules, pricing logic, approval workflows)
• Ensuring complete coverage — confirming no condition combination has been missed or contradicted
• Translating complex "if/then" business policy into a format developers can implement directly

When Not to Use

• Simple, single-condition logic where a sentence or flowchart is clearer
• Conditions with so many possible combinations that the table becomes unmanageably large (consider a decision tree or business rules engine instead)