In our opinion, execution should only be started when the business logic of the product is completely understood, which falls under the umbrella of “problem solving”. This is where we feel the design process would be able to square away, which would serve as the overall foundation for the final product to evolve to. Without it we have seen ciaos under Agile Development process that not only gives Agile a bad name, but also puts the product in danger of not launching.

Just to be clear, design phase doesn’t necessarily include execution of design mocks every time. It really depends on the project and the execution process needed. In your example with Agile, we agree with what you are saying.

To answer your question about how much design is enough… Again the major components that need to be identified during the design phase: the business logic of the product and client expectations, which includes: branding guidelines, sitemap, budget, timeline, ROI metrics, and design preferences. From there the logical next step is design execution (mock designs, translation to code, etc). Hope that answers your question.

I wonder if the design phase is really more about helping the client get some clarity on what the problem is and what a candidate solution might look like more than a fine-grained specification of the solution and a project plan that are written in stone.

Once the problem is better understood and a candidate design is established we could then identify finer-grained user stories and put them in a product backlog, which is the central planning mechanism for Agile development projects. This way we can achieve the best of both worlds: the client is investing the time and money to establish their vision, the candidate design provides a “visual guide”, and the resulting backlog gives us a way to evolve towards that design while at the same time allowing the flexibility to adapt the solution as we learn more during development based on actual end-user feedback.

Curious to know your thoughts, and it does beg the question: how much design is enough?

Wikipedia has an entry for the test track with info about the power lap rules: http://en.wikipedia.org/wiki/Top_Gear_test_track#Power_Laps