Problem statement is a general term for a document or set of documents that describes the need the project is supposed to satisfy.
The form of the problem statement varies widely and has no standards. Each organization develops its own format and content requirements.
The quality of a problem statement varies widely depending on the skill of the author(s). The problem statement may be as simple as a drawing on a cocktail napkin or as detailed as a government requirements specification.

The point is that project participants do not always have control over the form or quality of the problem statement.
The answer to this problem is to be prepared with a standard set of questions that will help you get the information that you need to proceed. In the following lessons, you will learn how to refine and clarify the problem statement by defining context, scope, and constraints.
The information that you gather will continue to change throughout the project. That much is inevitable. But documenting this information provides an objective means to measure the effect of proposed changes. This is very important, because if a thing can be measured, then it can be managed.