Sample of 16 is plenty if the effect is big enough.

It’s also not a sample size of 1, it’s a sample size of however many tasks you do because you don’t care about measuring the effect AI has on anyone but yourself if you’re trying to discern how it impacts you.

It's the most representative sample size if you're interested in your own performance though. I really don't care if other people are more productive with AI, if I'm the outlier that's not then I'd want to know.