Hierarchy of business processes and subprocesses 

There must always be an explicit link between business processes and the requirements.

It should start at a high level for the coverage perspective, but the requirements must be collected in detail. Asking the five Ws is always a good idea to ensure that enough details are collected.

Five Ws: Why, What, Where, Who, and When
When solution envisioning is performed, another crucial question, How, gets answered.

All the business processes that will be part of the initiative and each of their subprocesses must be considered for preparing the requirements list. There should never be a requirement without being linked to one or many processes; alternatively, there should not be any process/subprocess that does not have any requirements. Any such situation, wherein a requirement does not belong to any business process...