Earlier quoted context omitted.
Would it be accurate to say those 4 stones are about equivalent to one pawn in chess? As a back-of-the-envelope calculation, one pawn is 1/43 of your starting material in chess if the king is included as a four-point fighting piece. Four stones in Go comes to 1/45 of your expected endgame material as half of a 19x19 board.
It's hard to make a comparison like that because Go and Chess operate on fundamentally different models. Chess is about capturing a specific piece and putting your opponent in a position where they have no options but to lose; to that end, it's a war of attrition where players slowly lose resources until the game is over (note that I do not play chess at any significant level). In contrast, Go is about capturing terr…
It is very easy. The nature of the game is completely irrelevant. The question is what expectation of winning rate a 4 stone advantage gives to a Go player. For middle ranks, one stone is about 100 ELO-equivalent, or 64% winning rate. (I think it's closer at top dan ranks, would have to look up the statistics). 4 Stones is about 92% chance of winning between equal players.
The equivalent in chess is slightly more than 4 pawns advantage, or about a minor piece.