Common PRD Mistakes and How to Avoid Them

Why PRD Mistakes Matter

Many PRDs are written once and forgotten. They become outdated documents that no one reads. The problem is not that teams do not write PRDs — it is that they write them poorly. A PRD that sits in a folder without being referenced is worse than no PRD at all.

Mistake 1: Vague Requirements

Statements like "the app should be fast" are not requirements. Define specific performance targets — page load under two seconds, API response under 200 milliseconds.

The fix: Replace every vague statement with a measurable one. If you cannot measure it, it is not a requirement — it is a wish.

Mistake 2: Missing Acceptance Criteria

If a requirement cannot be tested, it is not a requirement. Every user story should have clear acceptance criteria that developers and QA can verify.

The fix: For every user story, write 2-5 acceptance criteria using "Given [context], when [action], then [result]."

Mistake 3: Ignoring Non-Functional Requirements

Security, accessibility, performance, and scalability are not afterthoughts. A feature that works but is inaccessible is not done.

The fix: Add a non-functional requirements section covering accessibility (WCAG 2.1 AA), performance targets, security, and scalability.

Mistake 4: Writing for Yourself

A PRD is a communication tool. Write for your audience — engineers need technical detail, executives need business context, designers need user context.

The fix: Before writing, identify who will read the document. Structure it so each audience can find what they need.

Mistake 5: Not Updating the Document

A PRD that was accurate two months ago but has not been updated is misleading. Requirements change. Markets shift. User feedback reveals new insights.

The fix: Treat the PRD as a living document. Schedule reviews at the start of each sprint. Update it when requirements change. Add a "Last Updated" date.

How to Fix These Mistakes

The sweet spot depends on complexity, but most PRDs benefit from being 3-10 pages. Provide enough detail that the team can build without constant clarification, but not so much that it becomes a burden to maintain.

Start with the core sections — problem, users, requirements, success metrics. Add detail where it matters. Remove sections that do not add value. If a section contains only generic filler, delete it.

What this product will NOT do is just as important as what it will do. Without explicit out-of-scope boundaries, every stakeholder assumes their feature is included. The out of scope section is your scope creep insurance.

Summary

A good PRD is specific, complete, audience-aware, and current. It covers functional and non-functional requirements, defines acceptance criteria, and sets clear boundaries. The goal is not a perfect document — it is a useful one.