Skip to content

2008 President · IL

Market Shares Corp. · fieldwork ended 2008-10-17 (18 days before the election) · 500 respondents · Live Phone

The poll said

Democrat 56% · Republican 32%

D+24.0

The certified result

Democrat 61.92% · Republican 36.78%

D+25.1

The arithmetic

  1. Poll margin = 56 − 32 = 24.00
  2. Actual margin = 61.918 − 36.781 = 25.137
  3. Signed miss = 24.00 − (25.137) = -1.137
  4. Absolute miss = |-1.137| = 1.137

The poll overstated the Republican by 1.1 points and had the right leader.

Where these numbers come from

Poll and result: 538 raw_polls.csv. Poll ID 16816, race ID 718 (538 database).