Republicans are likely being under-represented in mid-term polls.
As the saying goes, "Statistics Never Lie, But Liars Use Statistics."
The only poll that counts is the one taken on November 6th.
(Is that a sin?)
:)
It is not at all just with pollsters.
Most people I know never answer any call not from a number on their contact list.
This is proven in almost every internal exam, save Rasmussen's. They use typical voting histories to determine the split among Dems, Repubs, and Indies. Republicans are generally underrepresented by 7-10 %
To properly balance that is anethema to pollsters because they'd have to admit voters do not embrace their worldview. They may try to acknowledge the point with over representation of indies, but indies more likely go to Trump 2 to 1, imho.
And remember that so far DjT has rendered all past conventional wisdom to be bunk.