A decision model is a method used to show how data and knowledge are combined in a way that results in a specific outcome. These models can be applied to simple or complex decisions and are always specific and repeatable in nature.

Some key decision models to be aware of include the following:

• Decision tables: Each row (or column) in the table shows a rule and each column (or row) shows a condition for that rule. Once the rule and condition are considered together, there is a clear, acceptable "decision" or outcome.
• Decision trees: Similar to decision tables, decision trees show rules (as leaf nodes) and conditions (as branches). These are repeated until all the rules are considered against conditions to result in a specified outcome or "decision."

Both decision tables and decision trees are effective methods to apply when defining business rules for a business solution.

• Decision requirements diagrams: A decision requirements diagram is a model used to show much more complex business decisions that need to be made by a business or team. It shows information, knowledge, and decision-making using specific notation. It can be considered the bigger picture of decision analysis, and decision trees and decision tables often contribute to defining the elements of a decision requirements diagram.