Contrary to the definitions in the other answers, I'd assume that this refers to selecting positions from the database where that's the only difference in material - so "clean up a pawn" means that all the other figures are the same, that there isn't also a bishop vs knight difference, for example.
I really doubt if there was any attempt to check if there's some "strategic compensation" - how would you do that at a large scale? I doubt that even running a solid chess engine evaluation on all these positions is feasible, you need something where you can simply/cheaply filter positions from the database and then just count the winrate.
I really doubt if there was any attempt to check if there's some "strategic compensation" - how would you do that at a large scale? I doubt that even running a solid chess engine evaluation on all these positions is feasible, you need something where you can simply/cheaply filter positions from the database and then just count the winrate.