Business Analysis is the practice of identifying business needs and recommending solutions that deliver value to stakeholders. Solutions usually include a software component, but also extend to process improvements, organizational changes, strategic planning and policy development.
The 5 step analysis process can help to clarify the role of a business analyst. By defining the role, the analyst will be able to better create deliverables that meet stakeholder needs, discover expectations from primary stakeholders, and learn the "why" behind a project. This framework can be applied in a variety of settings from purchasing off-the-shelf software to building custom code, or from a multi-million-dollar project to a one-week project. Depending on the size and complexity of a project, analysts might spend more time in one step than in another, but in order to be successful a good analyst must complete them all.
It is important to note that If an analyst is added to a project after it has progressed past Step 1, they may consider backtracking to earlier steps in order to be more successful.