You mentioned that the idea came from you struggling to follow and keep up with the game action. You also know now that you need to differentiate your app idea from what's already available.

With that use case in mind I'd recommend watching a couple games while using currently available apps. Follow the play be play on the ESPN app, along with the shot charts. Do the same with NBA.com. If the currently available apps solve for the initial problem you have then that use case isn't differentiated enough for there to be value in developing something new.

From that point think about the other potential use cases - fantasy sports along with parents of athletes and/or scouts. I'm not a fantasy sport person myself, but given how many millions of dollars are in that I'm sure there are plenty of available apps that people use. That being said, because there's so much money in it, you could potentially carve out a niche if you can find a gap in features that fills a need. In going that route I'd recommend getting feedback from people who play a lot of fantasy sports on what apps they are currently using, and figure out if there are potential pain points.

The last use case mentioned was parents of athletes and/or scouts...now THAT sounds unique - because stats for youth sports aren't nearly as available as pro sports (and definitely not live tracking.) Also there's potentially a good amount of untapped money in that market - parents of kids playing sports spent a good amount of money. They'd also be looking for ways to help them understand. I know that personally - my nephew plays football for Stanford, and coming up through youth football leagues and high school football it was funny watching my sister try to learn the game as she watched her son. I could definitely see parents of those athletes being willing to shell out some coin for a well-designed app that helps them both track their kid's stats and at the same time get a better understanding of the game.