White player wins much more often. Is there a kind of statistics of how much more often? Mentally it seems to be half a point per game. At the same time, it is very easy to lose a tempo during the game. Castling long often leads to King b1 as an extra defense, for example. One tempo is immediately decisive in a zugzwang endgame, but a tempo from the very first move when all the peaces are in a useless mess, should quickly be diluted after a few moves, I would think.

A tempo advantage is normally temporary, one has to immediately turn it into a lasting advantage in material or position. Like keep on checking. So how come the one tempo advantage of white on the first move shows so clearly on the scoreboard?

I wonder if white's advantage says something generally (statistically) about the value of a tempo won during the game. If black wins a tempo in the midgame, shouldn't then black have the advantage as if he played white?