Harry Brignull’s post, Why you shouldn’t rush into a solution too quickly, about some of the slides from my presentation at OZIA has sparked off an interesting thread on the IxDA discussion list, How many alternatives, concepts, or sketches are enough?
The key point I was trying to make with the slides is that reaction to initial design sketches often sets the design direction and constrains the design space within which we explore potential solutions.
My intention with the slides was to warn practitioners of this, and encourage that they actively try to keep the design space unconstrained for as long as possible. It is difficult to do this, especially if you get positive feedback from the first sketches you share with colleagues/stakeholders/users.
As soon as we stop exploring different concepts and start iterating, we are optimising an idea rather than looking for different (innovative?) solutions. As another of my slides suggests, not every idea has the same potential:
So to give an answer to the question (How many alternatives, concepts, or sketches are enough?), I advise exploring as many different ideas as possible within the constraints (budget, time, etc) that are imposed upon you.
Ultimately how long you spend exploring different concepts depends upon the business objectives. If the business is trying to quickly squeeze another 5% revenue from the product in the quickest amount of time, fewer sketches and more iterations will probably get them there more quickly.
If the business has loftier ambitions, I would advise exploring more concepts and obtaining more early stage input from users before getting into an iterative process.
There isn’t a single set of user centred design activities, user centred design scales to fit. The activities and time you spend at each phase of the project must to be tailored to the specific objectives, aspirations and constraints of the project.