Cygnal - PA Senate - Fetterman +4

[Fmr. Gov. NickG]

Weighting by party registration instead of party ID is stupid for a multitude of reasons. People may not even know their status, they may misunderstand the question and answer with party ID anyways, and the registration numbers are currently trending R. It could be right or it could be wrong (in either direction) but either way it seems suspect to weight that way

Party registration is public information, so a pollster can verifiably stratify their sample by party registration, but not party ID.