Skip to content

2020 Senate · IA

InsiderAdvantage · fieldwork ended 2020-10-18 (16 days before the election) · 400 respondents · IVR/Live Phone

The poll said

Democrat 48.1% · Republican 43.4%

D+4.7

The certified result

Democrat 45.15% · Republican 51.74%

R+6.6

The arithmetic

  1. Poll margin = 48.1 − 43.4 = 4.70
  2. Actual margin = 45.152 − 51.740 = -6.588
  3. Signed miss = 4.70 − (-6.588) = 11.288
  4. Absolute miss = |11.288| = 11.288

The poll overstated the Democrat by 11.3 points and had the wrong leader.

Where these numbers come from

Poll and result: 538 raw_polls.csv. Poll ID 71465, race ID 6272 (538 database).