I think it's something you have to intuit, which means you're going to be wrong sometimes. I wouldn't hesitate on an idea because I couldn't figure it out, I would treat it more like a sniff test for whether or not you're entering a dieing market. Just an example, you're a parts manufacturer and you're deciding between R&D on ICE or Electric, you can't prove that electric motors will be the winner with any amount of data, but it's a pretty obvious intuition that targeting OEM parts contracts for ICE is not a good long game.
It can sometimes be very clear when you sit in the right part of the industry or community to have some kind of intuition on the matter. If you are in such a position you may have a fairly decent upper hand, and you could squander it if you wait for data or some Deloite report to tell you you're in a growing market.
It's also going to depend on how big your scope is. Are you looking to enter the "Toys" market or the "Specific kind of fidget spinner toy" niche? If it's just toys, then there's probably some general data to go by. If it's a specific niche you're probably going to be flying somewhat blind by necessity as there won't be any data yet.
It can sometimes be very clear when you sit in the right part of the industry or community to have some kind of intuition on the matter. If you are in such a position you may have a fairly decent upper hand, and you could squander it if you wait for data or some Deloite report to tell you you're in a growing market.
It's also going to depend on how big your scope is. Are you looking to enter the "Toys" market or the "Specific kind of fidget spinner toy" niche? If it's just toys, then there's probably some general data to go by. If it's a specific niche you're probably going to be flying somewhat blind by necessity as there won't be any data yet.