2018 House · IA-4
The New York Times/Siena College · fieldwork ended 2018-11-02 (4 days before the election) · 423 respondents · Live Phone
The poll said
Democrat 42.45% · Republican 47.22%
R+4.8
The certified result
Democrat 47.04% · Republican 50.37%
R+3.3
The arithmetic
- Poll margin = 42.45 − 47.22 = -4.77
- Actual margin = 47.037 − 50.368 = -3.331
- Signed miss = -4.77 − (-3.331) = -1.438
- Absolute miss = |-1.438| = 1.438
The poll overstated the Republican by 1.4 points and had the right leader.
Where these numbers come from
Poll and result: 538 raw_polls.csv. Poll ID 56709, race ID 300 (538 database).