Abstract: Many machines, particularly computers, execute decision processes during their operation. Such decision processes generally involve ascertaining the values of a number of condition factors and then determining the desired outcome in accordance with a predetermined decision function. This decision function may take the form of a number of individual statements relating condition-factor value combinations to particular outcomes. To facilitate end-user generation and modification of a decision function by generation and modification of a set of component statements, a structured representation for the component statements is presented to the user and statements are created and modified within this structured environment. Before a new or modified set of statements is accepted, it is checked for consistency between statements.