2012 House · IL-13
Impact Research · fieldwork ended 2012-10-20 (17 days before the election) · 400 respondents · Live Phone · partisan sponsor (DEM)
The poll said
Democrat 48% · Republican 39%
D+9.0
The certified result
Democrat 46.21% · Republican 46.55%
R+0.3
The arithmetic
- Poll margin = 48 − 39 = 9.00
- Actual margin = 46.209 − 46.549 = -0.340
- Signed miss = 9.00 − (-0.340) = 9.340
- Absolute miss = |9.340| = 9.340
The poll overstated the Democrat by 9.3 points and had the wrong leader.
Where these numbers come from
Poll and result: 538 raw_polls.csv. Poll ID 51360, race ID 5040 (538 database).