I like that approach. To me the essential question of product-market fit is whether you are delivering sufficient value to your users. But I think "sufficient" has at least three characteristics that one can measure.
One is whether the user likes it enough to keep using it. I think that's well captured by the "how disappointed" approach (and actual usage stats). Another is whether they'll be evangelical about it, and I think that's measurable with Net Promoter Score (and actual viral behavior). And a third is whether you can build a sustainable business, which early on can be pretty simple, but eventually requires a fairly complex numerical analysis.
I think a numerical approach like this one is especially valuable if the business isn't self-funding. Because a) you need to be able to prove the value of the equity you're selling, and b) if you don't price your equity properly, it's just a gift to the VCs who do that work.
One is whether the user likes it enough to keep using it. I think that's well captured by the "how disappointed" approach (and actual usage stats). Another is whether they'll be evangelical about it, and I think that's measurable with Net Promoter Score (and actual viral behavior). And a third is whether you can build a sustainable business, which early on can be pretty simple, but eventually requires a fairly complex numerical analysis.
I think a numerical approach like this one is especially valuable if the business isn't self-funding. Because a) you need to be able to prove the value of the equity you're selling, and b) if you don't price your equity properly, it's just a gift to the VCs who do that work.