Inclusive design

Designing one product that works for as many people as possible regardless of age or ability, without a separate special version — covering physical, sensory and cognitive differences.

"Who does this exclude, and what would let them in?" It produces a specific barrier and a specific design change instead of an opinion.

One channel always excludes somebody: a beep fails deaf users and noisy places, a colour change fails colour-blind users and bright sun. Sound plus sight covers both.

One arm; a broken wrist for six weeks; holding a toddler. All three need one-handed use, and only the first appears in a disability statistic.

The middle value of one measurement across a population: half of people measure less and half more on that dimension. It says nothing about any other dimension.

Nobody is at the 50th percentile in several dimensions at once, and combining a few such requirements leaves a band far narrower than half the population.

Where comfort rather than access is at stake and adjustment is genuinely impossible — a fixed seat pitch, say. Even then, name who is disadvantaged and what alternative exists.

State who the product does not serve and why, bound the exclusion with real data, and provide an alternative where one exists — rather than claiming it suits everybody.

Setting each requirement from the user at the limit rather than the average: reach, force and readability from the least capable user, clearance and capacity from the largest.

Ask whether it lets somebody IN or lets something THROUGH. Access requirements come from the least capable user; space and capacity requirements from the largest.

Nobody is designed out, because the requirement is met across the whole range; and one product serves everybody, so there is no special version to design and stock, and no stigma.

Dropped kerbs, designed for wheelchairs and used by every pram and suitcase; lever door handles, an arthritis solution now standard; subtitles, for deaf viewers and watched by about a third of viewers.