The document outlines decision rules in Pega, detailing types such as decision tables, decision trees, map values, and when conditions, along with their functions and comparison criteria. It explains how to use fork and decision shapes in flow definitions, emphasizing scenarios for each decision rule type. The guidelines include when to apply map values, decision tables, decision trees, and when rules based on input conditions.

1. Pega Test Topics
Decision Rules % of Exam: 6%
■ Decision Rule Types
– Describe the following types of decision rules and their function
􀁸 Decision Tables
􀁸 Decision Trees
􀁸 Map Values
􀁸 When Conditions
– Compare different decision rule types and identify when to use them
Exam Blueprint 11
■ Fork and Decision Shapes
0 Explain the difference between fork shapes and decision shapes in a flow
Definition.
A decision rule is usually called from a flow and is used to make a decision about the
path the flow should take. It can also be called from a declarative rule.
A Decision table contains one or more rows, each containing test conditions and a result
to return. Evaluation proceeds top-down. When all cells are true for a row, the result of
that row is returned. If no row is true, the table returns the Otherwise row’s result. Empty
cell defaults to a true. Decision tables are instances of the Rule-Declare-DecisionTable
class.
A decision tree uses if/then logic to return a value based on rows of property values, and
computations (including comparisons). It is an instance of Rule-Declare-DecisionTree
class.
A Map value rule is a rule that converts one or two input values to a calculated result
value using a matrix to look up the result. Map values can be cascaded – one map value
calls another which calls a third, etc. Thus an output can be decided based on more than 2
inputs. Map value rules can be called from a flow, another map value, an activity (using a
Property-Map-Value method), a declare expression. They are instances of the Rule-Obj-
MapValue rule type.

2. A When Condition rule defines a true-false test based on comparing one or more
property values with constants or other property values. It is an instance of the Rule-Obj-
When rule type.
When to use what:
1. Use map values when you need to make decisions based on *ranges* of one or
two inputs. Note: map value rules can be cascaded.
2. Use decision table when the tests are based on the same set of properties and data
is easy to see in a tabular form.
3. Use decision tree when the tests tend to be for different properties and the
conditions are complex (like nested if/then/else conditions).
4. Use When rules when you want a true/false test result.
Fork and Decision Shapes
1. Use fork when you use a when rule to make the decision
2. Use a decision shape when you use a decision tree or decision table to make the
decision.