Moving from low- to high-fidelity prototypes as your project progresses is one of the design lessons Irene Au shares in her talk The Architecture of Creative Collaboration. Too often Au has noticed software teams jumping straight into high-fidelity mockups instead of starting their projects with low-fidelity sketches and increasing the level of fidelity with each iteration.
Why start with low-fidelity? As a designer, why shouldn't you try to express your vision in as much detail as possible?
Au says that in the early stages of a software project, high-fidelity prototypes make teams focus on the wrong things and communicate clarity that's not actually there. Early stage conversations should revolve around high-level concepts like values and priorities. But when teams huddle around high-fidelity mockups, they start discussing the UI details presented to them—not vision and meaning.
Au herself learned that an architect agency who she was a client of sometimes hides high-fidelity drawings from their clients. The agency presents them instead with low-fidelity sketches in order to manage expectations and help clients focus on the right things at the right time.
I have previously touched on the subject of high-fidelity prototypes when I argued that mockups make it harder for teams to adopt iterative product development practices (here is a link to the post). In addition, when you start out with mockups, you do most of your design work up front instead of allowing the designs to grow and adapt as the team learns new things about the problem space.
Markers and sketchpads are still as important tools for designers as prototyping applications.
A full transcript of Irene Au's talk (as well as the talk itself) can be found at 99u.adobe.com/videos/55969/irene-au-the-architecture-of-creative-collaboration.