This week I'm thinking about the importance of requirements definition in product development. The most successful programs I've worked on have had a Product Requirements Document defined up front. It may seem obvious, but clearly stating the design requirements up front helps our prototyping efforts be more productive.
What is a Product Requirement and PRD? A product requirement is a single statement which defines an important feature of a product. Each requirement is discrete and measurable. Each requirement specifies an outcome without defining a specific method or process that will achieve the requirement.
A Product Requirement Document (PRD) is just a long list of Requirements. Simple, right? This list is an opportunity for each team member to stake their claim in defining the direction that the development team will be going. Each stakeholder has their own needs: industrial design, software, hardware, firmware, mechanical, electrical, manufacturing, etc. Everyone gets to have input.
Each individual requirement will be mapped to a Verification or Validation test, so we must make each one clear and measurable.
Well Written Requirements: 1. Functional Requirement - Device must support 15W wireless charging 2. Regulatory Requirement - Device labeling must comply with 21 CFR - Part 810 3. Usability Requirement - Display size must be between 4.0" - 7.0" (measured diagonally)
Unclear Requirements: 1. Device must be lightweight and have a phone-sized screen What is lightweight? How do we measure pass/fail on lightweight? What is a 'phone-sized screen'?
2. Handpiece must be bluetooth and be manufactured with no more than two molded parts. Why are molding, part quantity, and bluetooth requirements combined?
What Requirements Should I Write Down? Don't let analysis paralysis take over. Product Requirements Documents are living documents. Start a document, and iterate. Your team may choose to revision control the document with clients or stakeholders to ensure that the team is aligned.
Writing a PRD doesn't have to be challenging or difficult. Start writing your requirements down, you'll be surprised at the clarity of vision that comes out of it.
Pro Tip for Faster Requirements Definition Build a prototype and put it in front of your users and LISTEN. You'll be surprised how many requirements you can find.