We usually express these steps procedurally, in terms of who performs the task, what tasks are performed and when the actors perform them. Decisions of when an actor should perform a task must take into account the necessary dependencies, sequences and opportunities for parallel execution. Behind each task or step are the business rules that guide the actor's behavior. Use information Make a decision about the state of something relevant to the task Make a decision about an action to take Take the action Record the results of the task's decisions and actions Behind each use of information and each decision are business rules for interpreting the information properly and for taking proper action. Many different kinds of business rules exist and each type is expressed in a unique way.
Some people find that it is helpful to define templates for each kind of business rule.
You can create one business rule template that leads to logical conclusions, another one for business rules that prescribe a mathematical calculation and another template for business rules that either constrain or enable actions. Whether you decide to use natural-language templates, diagrams or another format, you should express a business rule first and foremost in a form your business audience will understand. A challenging aspect of expressing business rules is choosing a language or format that businesspeople understand and yet is precise enough to avoid ambiguity. A business rule's purpose is to serve as a basis, justification, guidance system or intelligent insight for using information, making decisions and having actors carry out a business task. A business rule explains why a decision is reached or why an action is taken, but it doesn't describe how it is done.