I have an idea and talked to about 14 people who have all said it's a good to great idea.
Based on this positive feedback, I have built (in about a week) a very primitive semi-working prototype that demonstrates at least what I think the idea could be. I want to use this prototype to test whether or not people like the idea or not; and to modify it based on their feedback.
I see from what I've built that the idea could go in many different tangents, including throwing away everything that I've done, and starting in a different direction; the pivot. At a minimum it's a platform to initiate a conversation.
Several questions come to mind.
First is, how many people should I talk to? One said a dozen is a good sample size, but is it?
Second is, of the people I talk to, how do I tell the difference between the early adopters and the customers? Is it nothing more than "show me when it's done" vs. "that's interesting, I'd buy it, but you could do it this way". Or is there a more rudimentary strategy?
Third is, what if the opinions of the people i talk to all vary so much that I cannot hone down anything with what I have. Is that a pivot point? -- because I fundamentally cannot validate my tests; with the work I've done. At that point, do I only deliver the thing that is most in common with all of them? In other words, to I keep looking for those who agree or use whom I've talked to as the "pulse" of the market I'm trying to target? It kind of goes back to question #1.
In statistics as in life 12 is a small sample size when you think of an entire target market. But let's look at your 12 samples, are any of them your friends/family people with a vested interest in keeping you happy? If so you need to discount them, sorry but while they may have your best interest at heart they are ultimately likely to be biased.
While building a product price is not always about the bottom line it is still useful to gauge peoples interest, I find questions such as:
How much would you spend on this product monthly if available now?
Assuming they say they would spend some money monthly.
If I give you 20% off the value you just quoted me, will you sign up now in its current state?
If they say yes to the later they are a customer, if they say no either you have pitched wrongly or they are unlikely to become a customer in the near future. Now I'm not suggesting you actually give them 20% off a price they originally picked but it will identify and gauge their interest quickly and easily, I would say if you do then use the customer for further feedback you look to give some sort of discount however.
In terms of how many people should you validate against, well how big is your target market, how many sales do you need for a viable product, how quickly do you need to acquire sales to reach stability.
In most industries and niches you are talking 10ks potential customers and relatively to reach minimal viability say 20 or 30, then you would be looking at 15-20 "customers" willing to put their cash their for validation. If you need 1000 sales to reach viability then you would be looking around 400-600 people to validate the idea and be ready to put cash on the table.
These are very conservative numbers based on limiting exposure and risk, but also expect low growth. Ultimately it is balancing act good luck finding your initial customers.