2010 House · ID-1
Mason-Dixon Polling & Strategy · fieldwork ended 2010-10-21 (12 days before the election) · 400 respondents · Live Phone
The poll said
Democrat 44% · Republican 41%
D+3.0
The certified result
Democrat 41.28% · Republican 51.02%
R+9.7
The arithmetic
- Poll margin = 44 − 41 = 3.00
- Actual margin = 41.279 − 51.017 = -9.738
- Signed miss = 3.00 − (-9.738) = 12.739
- Absolute miss = |12.739| = 12.739
The poll overstated the Democrat by 12.7 points and had the wrong leader.
Where these numbers come from
Poll and result: 538 raw_polls.csv. Poll ID 32661, race ID 4587 (538 database).