Start with imperfect metrics and iterate

I think everything can be measured to a certain degree. Not precisely necessarily, but you can get enough of a swag to be useful. So, by trying to measure things, you'll start learning how to measure things.

You just have to get comfortable measuring something that's not perfect, but you can actually measure and reporting on it and then the measure that's imperfect as people ask questions, that's an opportunity to educate people.

Even if you have a sample size of 30, the data you get back, generally, does not change but its precision will. So mathematically speaking, you're going to get the same level of trends, but the precision at which you understand those trends will become more deep if you have more data.

Every idea is so cheap at that scale. You could do things that don't scale dramatically better with 30 people than at 100 if you're testing.