Promoted by Steven D

At the start let me say what this isn’t.  This is not an unskew the polls diary.  In fact, this is the opposite: this is a data driven diary that is based on one simple table.  These are the averages for all polls in October and November where the results found a margin of less than two points.  Honestly I didn’t think I would find anything.  But the evidence is clear.  There is a consistent bias against Democrats.  

Why am I the only one seeing this?  Honestly, most don’t have data that goes back as far as I do (I think 538 goes back to ’04).  

So why would this happen? In June of 2012 I wrote a diary entitled “Are cell phones resulting in biased polls against Democrats?”.  In it I noted that minorities and the young were far more likely not to have a landline than the rest of the population.  This became apparent in the aftermath of 2012.

Something else no one seems to have noticed.  Every telephone poll of the national 2012 Presidential Election Understated Obama’s margin.  The last time this happened was 1980!  This is not new, though.  The Generic Ballot polling was pretty bad in 2010 as well.

Look at the table.  The average polling error for the Senate has been:
2012:  -5.32
2010   -3.21
2008   -2.28
2006   -2.68
2004    2.33
2002    4.25
2000    -3.91
1998    -6.27

So in the last 4 elections, Democratic support has been underestimated by over 2 points!!  In the last 8 elections 6 have seen significant understatement of Democratic Support in close races.

More tomorrow.

The results below are taken from my database of 11471 polls from 1998 to 2012.