2010 Senate · IL
Impact Research · fieldwork ended 2010-10-15 (18 days before the election) · 601 respondents · Live Phone · partisan sponsor (DEM)
The poll said
Democrat 41% · Republican 36%
D+5.0
The certified result
Democrat 46.42% · Republican 48.02%
R+1.6
The arithmetic
- Poll margin = 41 − 36 = 5.00
- Actual margin = 46.416 − 48.015 = -1.599
- Signed miss = 5.00 − (-1.599) = 6.599
- Absolute miss = |6.599| = 6.599
The poll overstated the Democrat by 6.6 points and had the wrong leader.
Where these numbers come from
Poll and result: 538 raw_polls.csv. Poll ID 32603, race ID 1518 (538 database).