Weight values are optionally set to indicate the magnitude of a problem but are not necessary to a Business Impact Manager installation. When a root-cause event occurs, the Business Impact Manager sums the weight of the affected elements for a total impact, which is displayed with the root-cause: the greater the impact number, the greater the problem. You can assign weights by class, instance name, and instance. Wildcards can be used when you assign weights by instance.
There is no particular method to use to assign weights. Weights measure the relative importance of aspects such as revenue, contractual requirements, reputation, cost and so on.
One strategy to follow when assigning weights is to develop weights from parent classes, through subclasses, down to particular instances. If there is any overlap, the instance weight is used before the class weight, which is used before the parent class weight.