Even though we’ve prioritised what we believe the minimum viable product is, we’ve still no idea if we can deliver it for the time frame or budget we’ve allocated. The scope feels right, but is it doable? When the developers estimate the stories that have been identified, they will make assumptions. These will be geared around how they might implement each story in the simplest way. Design is probably not at the forefront of their mind, and it is for this reason that having a designer as part of the process, supporting the team in explaining what the story means for a customer, means that the developer estimates are informed by design.
By being part of the estimation process, the designer ensures her vision for the stories is ...