2008 Senate · IA
SurveyUSA · fieldwork ended 2008-10-28 (7 days before the election) · 658 respondents · IVR
The poll said
Democrat 61% · Republican 35%
D+26.0
The certified result
Democrat 62.66% · Republican 37.26%
D+25.4
The arithmetic
- Poll margin = 61 − 35 = 26.00
- Actual margin = 62.656 − 37.261 = 25.395
- Signed miss = 26.00 − (25.395) = 0.605
- Absolute miss = |0.605| = 0.605
The poll overstated the Democrat by 0.6 points and had the right leader.
Where these numbers come from
Poll and result: 538 raw_polls.csv. Poll ID 16572, race ID 1554 (538 database).