> One way you could make this clearer is replacing the phrase "can be much more productive" with a more specific goal that's more obviously good.

I think that specifying a metric would dilute the message; replace it with whatever your goal is. Working at a startup may help you be more productive in achieving it simply because there are fewer people/processes to hinder you. Not everyone has the same goal, but being able to point to something useful and say "I did that" is meaningful to me.

"I get more done in a week here than I did in a month at [BigCo]"

^ That's a direct quote from someone who recently came to us from a large established company. They really liked seeing the noticeable impact of their personal contributions. I didn't ask them to compare the two work environments; they were just blown away by how much they could accomplish when they weren't being held back.