Finding twelve people

Twelve is not a magic number, but it is enough to stop you generalising from your two most enthusiastic friends and small enough to finish in three weeks alongside everything else. Below about eight you are still hearing individuals. Past about fifteen, on a well-defined problem, you usually start hearing the same four answers.

You almost certainly have more access than you think. Your own family business and its suppliers. The trader in the market who has the problem every week. Alumni groups and the college placement cell. A WhatsApp group for a profession, where one honest message — "I am a student researching how X actually gets done, fifteen minutes, no selling" — is often enough. Local associations, a shopkeepers association, a clinic, a coaching centre. The people at the counter of a business like the one you are studying, at the hour when they are not busy.

Two rules. Do not pay for opinions, because paid enthusiasm is not evidence. And do not talk only to people who like you: at least four of your twelve should be strangers, because friends and family will protect your feelings and their protection is the noise you are trying to remove.