These are the factors affecting span of control:
1. Geographical Location, if the branches of a business are widely dispersed, then the manager will find it difficult to supervise each of them, as such the span on control will be smaller.
2. Capability of workers, if workers are highly capable, and do not require much supervision and can be left on their own, eg: Theory Y type of people, need not be supervised much as they are motivated and take initiative to work,as such the span of control will be wider.
3. Similarity of task, if the task that the subordinates are performing are similar, then the span of control can be wider, as the manager can supervise them all at the same time. However, of course the capability of the supervisor has to also be taken into consideration.