What does "pp" mean?

"pp" is short for percentage points of win rate. +1.0pp is about one extra win per 100 matches.

Zero means an even match-up, not a zero win rate. A hero reading +2.1pp sits a little above even against the enemy line-up, and one reading -1.4pp sits a little below it.

Why it isn't just a percentage

Every win rate here is pulled toward even, so a hero played twice at 100% can't top a list, and the community data is re-centred on 50% when it's aggregated. That leaves a real spread of about six points, so a genuinely strong pick would print as "52.1%" and read like a coin flip. Showing the difference instead keeps the size of the effect and drops the baseline that was doing the lying.

The ± number beside it

That's the margin of error, in the same unit. When it's wider than the figure next to it, the reading is inside its own noise - which is how you tell "genuinely even" apart from "not enough matches to tell yet".

Two numbers that aren't pp

A figure marked team is the change in your whole side's summed edge if you made that swap, not one hero's rate. Counter ratings carry no unit at all. Impact (1 to 99) is a rating of how you played, not a win rate: 50 is the typical minute on that hero at your rank. If you see pp, it's win-rate points.