Needs assessment, business case, charter and baseline. Establishing what a project is for, before anyone argues about whether it delivered.
Terms
The document justifying an investment, evaluating the benefit, cost and risk of alternative options and giving a rationale for the preferred one.
Structured work establishing the gap between an organisation's current state and the state it requires, in evidence, before any solution is named.
The written output of a needs assessment: the gap an organisation has to close, described with no product, technology or supplier named in it.