Product Validation

Marty Cagan argues that product managers should validate a product specification before handing it to engineering, rather than trusting the spec and planning to adjust after beta feedback. Because prototyping costs have fallen sharply, validation is now affordable for nearly any product. He describes three checks: feasibility (can it be built), usability (can users figure out how to use it), and desirability (do users actually want it). He concludes that finding surprises early is far cheaper than discovering them after engineering inertia has set in.

01Key takeaways

• Validate the product spec before engineering begins, since changes become far costlier once real building starts.
• Test feasibility early with engineers and architects to uncover technical dead-ends before time and money are lost.
• Run usability tests on real target customers, expecting several iterations before a workable user experience emerges.
• Simulating complex back-end processing is acceptable during usability testing, as long as the user experience is what's evaluated.
• Check desirability separately: users may learn a task easily yet not care about it, so test whether the problem matters.
• Treat prototypes as scale models for learning, not as the foundation to build the final product from.

02Key sections

The cost of skipping validation

Teams often overtrust their specs and assume beta feedback will fix problems, but beta comes too late for major changes. The author frames validation as the product manager's responsibility.

Feasibility testing

Engineers and architects should explore technologies early to surface obstacles that could make the product unbuildable in its timeframe. Known technical risks should be addressed upfront.

Usability testing

Designers build prototypes that real target customers use, revealing missing requirements and unnecessary ones. Back-end complexity can be simulated, as the focus is the user experience.

Desirability testing

The final question is whether users care enough to buy. This can share prototypes with usability testing, but asks whether people value the tasks being solved rather than whether they can complete them.

Prototype fidelity and management understanding

The high-versus-low fidelity debate is now largely moot because high-fidelity prototypes are cheap and yield better feedback. Managers now generally understand prototypes differ from the real product.

03From the post

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04Frameworks mentioned

Summary and takeaways written by PM Atlas; quotes are short excerpts. © the original author.