But digging a bit deeper today I found a couple of articles that got me thinking.
Initially I found them quite persuasive.
From this piece by Steve Kaire the point that stood out for me was the first: 'Your idea should be original and unique'. Hard to argue with that.
And in Conquering the high concept James Bonnet suggests four requirements for high concept pitches:
1. The fascinating subject,
2. The great title,
3. The inciting action, which is the problem of your story, and
4. The hook, which reveals the uniqueness or special circumstances of your story.
Again, hard to argue with.
But on reflection I'm not sure if you can be this prescriptive.
Yes, an idea must be fascinating else why would anyone commission it. But how do you define fascinating in this context? Bonnet can't. It's completely subjective. Come to think of it, 'Original and unique' only really means: hasn't been done before in precisely this way or if it was it was a long time ago and no one will remember.
Likewise 'great title' - overwhelmingly a matter of opinion.
Meanwhile, the inciting action and the hook are (arguably) standard script requirements, that, I think, might or might not be part of a high concept pitch.
Instead, I think the key to high concept pitches is in what Bonnet says about why they're important: because commissioners don't have time to try and work out what your script is going to be about.
So, what high concept really means is expressing an idea in the clearest and most concise way possible. Everything else is just a matter of opinion. (Actually, even 'expressing an idea in the clearest and most concise way possible' is a matter of opinion, but never mind)
So, there aren't high concept pitches and low concept pitches. There are just good pitches and less good pitches.