This is a crucial information for managers since they need to understand which are the resources available from a human resources standpoint. A hierarchical organizational structure normally has well defined boundaries that allow the manager to fully understand who are part of his team.
Nevertheless, when job positions are not properly designed, a confusing situation might emerge where a person has two or more bosses. This is important to avoid since it creates conflicts within the structure and guidelines become unclear for the subordinate. A clear definition of the span of control allows the manager to plan, organize and divide the work load among his team according to his work method, assigning each team member the duties he thinks they are capable to handle, according to their skills, knowledge and academic background.
Managers can also implement metrics to evaluate the performance of their span and influence them to increase their productivity depending on the results obtained.