Are refs calling NWSL and MLS games differently?

A few of us have gotten the impression that referees in NWSL games are awarding tons of penalty kicks but not many yellow cards. Are we right?

Sort of …

So the PKs, aside from games involving Sky Blue, aren’t that far off. But yellow cards? A rare sight in an NWSL game.

If you’d like to check my work, have at it …