Q&A: how much evidence is sufficient for decision making?

I was recently asked this question:

Do you have a rule of thumb for deciding how much evidence is sufficient for decision making? I often see decisions made on the basis of a sample of one.

Here’s my answer:

Hi there,

Thanks for the question. I don’t have a general rule of thumb for sample sizes for user research as it depends on a few things, including:

What level of accuracy you’re looking for from your research (statistical rigour) How large your target user persona segments are What kind...