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2014 Senate · IA

Public Policy Polling · fieldwork ended 2014-10-15 (20 days before the election) · 714 respondents · IVR · partisan sponsor (DEM)

The poll said

Democrat 48% · Republican 47%

D+1.0

The certified result

Democrat 43.76% · Republican 52.10%

R+8.3

The arithmetic

  1. Poll margin = 48 − 47 = 1.00
  2. Actual margin = 43.761 − 52.100 = -8.339
  3. Signed miss = 1.00 − (-8.339) = 9.339
  4. Absolute miss = |9.339| = 9.339

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 33736, race ID 26 (538 database).