I recently learned that the German polls also rely on random calls - but worse than that, they only use the publicly registered phone numbers, i.e. the ones in

I recently learned that the German polls also rely on random calls - but worse than that, they only use the publicly registered phone numbers, i.e. the ones in the phone book. That list mostly includes landlines, and biases towards older landlines as well (since IIRC phone book registration switched from opt-out to opt-in at some point). So the polls strongly overemphasize older voters (because no one else has a landline phone anymore).