How many person's inputs are required to validate the startup idea? At what point I can know that my idea is validated?
Samples are traditionally 100+ people. Can you get 100 customers? How many customers (users too) do you have participating on the idea?
Once you've shared it past friends and family, strangers are interested in what you're doing I believe that is all that is needed for a product/service to be validated.
Feel free to call me on message me on LinkedIn to discuss this more in detail.
Idea validation is not necessarily something that is set the same for everyone. It depends on your product and market.
For example, if you are selling a physical product, have spent $1,000 in launching the business and creating prototypes or marketing to get pre-orders then your validation could be around the number of orders that gives you back that $1,000 or it can be based on margin, say, when you get $5,000 in pre-orders so that it gives you enough to produce more for the next set of orders.
Validation can be simpler still, if all you have is an idea you can create simple marketing and landing pages and see if you can get 1,000 email registrations. These amounts may sound little but for the new entrepreneur and new marketer this number can be difficult to achieve. If you get to that without asking only friends and family then the validation is not only in your idea but also in your ability to market the idea.
Statistically, a thousand people is representative of any opinion and attitude. What seems to work well with smaller numbers is a clear intent to purchase the product and better yet, actual customers or beta testers. So in other words, if through a Kickstarter or similar small marketing campaign you get actual revenue going, this is almost better than positive confirmation of need by a larger sample population. Key is to get niche right and to focus on competitive advantage. Hop on a call and we can confirm your progress, plan for success.