Rework in software projects rarely comes from technical errors. It almost always comes from requirements that no one questioned. That is, a developer can build exactly what was asked of them, with good code, good tests, and still deliver something that doesn't work because what was requested was not what the business needed. That type of rework does not appear in any software quality report. It appears as 'scope changes', as additional meetings, as a delivery date that is pushed back for the third time.
Why this goes unnoticed until it's too late
An ambiguous requirement looks perfectly fine at the moment it is approved. It sounds clear, everyone nods in the meeting, no one asks for more detail because asking too much feels like distrusting the team or delaying the project. The problem is that 'sounding clear' and 'being precise' are not the same, and that difference only becomes visible when the developer has already built something, and that something is not what the manager had in mind.
By then, the cost is no longer just time. It is of two versions of the same functionality that now need to be reconciled, of a team that starts to doubt every future instruction, and of a project that is delayed not by technical complexity, but by something that could have been resolved with a well-asked question at the beginning.
Before and after: how the difference looks
Example 1 — Approval of discounts
Ambiguous: 'The system must allow approving special discounts for important clients.'
Well written: “As a sales manager, I want the system to automatically block and send me for approval any quote with a discount greater than 15% off the list price, to prevent discounts that affect the margin from being granted without my review. If the discount is equal to or less than 15%, the system should automatically approve it, without 'important client' being a valid exception criterion.”
Example 2 — Inventory Report
Ambiguous: “We need a report that shows the inventory status in real time.”
Well written: “As a warehouse manager, I want to see on screen the available, committed, and in transit units by warehouse, updated every time an inventory movement is recorded, to make dispatch decisions without relying on outdated reports. Additionally, as a manager, I want to receive this same information as an exportable file every morning at 6:00 a.m., to review it before my first meeting of the day.”
Why format matters as much as content
There is a reason why “As a [role], I want [functionality], for [benefit]” became a standard in the software industry: it forces you to answer three questions that a loose requirement may leave implicit. Who needs it, what exactly do they need, and why do they need it.
That third part the "why" is the one that is most often skipped, and it is the most revealing. A requirement without that explicit purpose can be technically well constructed and still not solve the real problem, because no one verified that the functionality and the business objective were aligned. When the "why" is written down, anyone who reads the story: the developer, the manager, a new consultant on the project, can evaluate whether what was built truly fulfills its purpose, not just if it met the literal instruction.
The format, by itself, does not eliminate ambiguity, that is done by the acceptance criteria and the verifiable conditions of the previous examples. But it does enforce a discipline of thought: writing a requirement in this structure makes it much harder to leave an intention half-finished without noticing.
Checklist before approving a requirement
Before accepting a requirement as good, it is worth it for the approver to ask themselves these questions:
• Does the requirement define a verifiable condition, or just a general intention?
• Are edge cases and exceptions resolved, or just the ideal case?
• Is it clear who does what, at what time, or are there roles or steps implied that are "taken for granted"?
• Did someone from the technical team and someone from the business read the same requirement and understand exactly the same thing?
• If it were given to someone who was not in the meeting to read, could they build the correct thing without having to ask anything else?
If any of these questions do not have a clear answer, the requirement is still not ready to be approved and approving it like this does not save time. It only shifts it, with interest, to later in the project.