My experience was, after investment, we brought in (as cofounders) a really experienced team of marketing professionals (one from a big name, like Oglivy, and another who ran online marketing for a major bank). We had business metrics, we measured progress of focus groups, interviews, surveys, etc. The kind of metrics corporations use to "save money by making cheap mistakes on paper during planning instead of making expensive mistakes in production".
If I had to do it all over again I would have just built the wrong thing, and delayed the cost of finding the product/market fit until I raised more money with that wrong thing. Because metrics against a bright and shiny object, even the wrong object, are perceived as more valuable than metrics that bring you closer to building the right object in the first place.