Do surveys and potential user interviews count? Does first hand knowledge of the problem count?
My rule of thumb is only sales count.
If I can't turn an idea into a sale by end of day (via completely manual means), I move on to another idea.
For example. Have an idea + mention it places you cultivate (where you post or interact with people) + if you get a sale by end of day (use a PayPal manual transaction), then you might have a good idea.
Meetup groups + CoWork space talks are good too.
If you can give a talk to a group + generate a few manual PayPal transactions, you may have a winner.
No sales == Get a new idea.
That's my rule for myself.
