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Leo combines polls with other information to predict how many Senate races Democrats and Republicans will win in 2014.

Leo uses:

Historical results from the Open Elections project, CQ Press Voting and Elections Collection, Dave Leip’s Atlas of U.S. Presidential Elections, and the Federal Election Commission.

Fund-raising data from the Federal Election Commission. Biographical data from Project Vote Smart and candidate websites.

Polls aggregated by Pollster, the Roper Center for Public Opinion Research, the U.S. Officials’ Job Approval Ratings project, Polling Report, Gallup, Talking Points Memo, The Argo Journal, Real Clear Politics and FiveThirtyEight.

Brief instructions

  • Please make sure the following R packages have been installed: gam, gtools, lubridate, maps, RJSONIO, gdata, plotrix, zoo

  • Change directory to the top-level working directory of this Git repository.

  • Run: Rscript master-public.R

  • Prediction output can then be found in the data-publisher/public/_big_assets/ subdirectory.

Sample output data in /data-publisher/public/_big_assets

dem chance
44 0
45 0
46 0
47 0.05
48 0.25
49 0.15
50 0.3
51 0.15
statePostal secondary probability mean scale office dem rep
AK 0.0675992536643285 13.3371042222312 6.37706218633251 ak-senate-class-ii-2014 mark-begich joe-miller
AK 0.672480368777626 -0.369330147923164 6.40862522137136 ak-senate-class-ii-2014 mark-begich daniel-s-sullivan
AK 0.259920377558046 -1.42864965262853 6.43282051331378 ak-senate-class-ii-2014 mark-begich mead-treadwell
AL 1 -92.2586242817344 13.0668255800746 al-senate-class-ii-2014 NA jeff-sessions
AR 1 -0.588349828909989 5.43497477566511 ar-senate-class-ii-2014 mark-pryor thomas-cotton-1
CO 1 2.75130137738909 5.32999951709124 co-senate-class-ii-2014 mark-udall cory-gardner
DE 0.0485586168626867 22.1226995091985 12.2918575405219 de-senate-class-ii-2014 christopher-a-coons tom-kovach
DE 0.951441383137313 24.462299974418 12.2976359697371 de-senate-class-ii-2014 christopher-a-coons christine-o'donnell
  "date": "2014-04-22T13:19:49-0400",
  "data": [
      "dem-pct": 49.428,
      "state": "AK",
      "office": "ak-senate-class-ii-2014",
      "fips": "2",
      "nyt-rating": 4
      "dem-pct": 4.1438E-10,
      "state": "AL",
      "office": "al-senate-class-ii-2014",
      "fips": "1",
      "nyt-rating": 7
      "dem-pct": 45.693,
      "state": "AR",
      "office": "ar-senate-class-ii-2014",
      "fips": "5",
      "nyt-rating": 4
  "continuingSeats": {
    "dem": 34,
    "rep": 30
  "nationalErrorScale": 0.40797,
  "upsetProb": 40,
  "houseEffect": 3.5,
  "mt": 85,
  "mtNum": "17",
  "mtDenom": "20",
  "aan": "an"
office date dem
ak-senate-class-ii-2014 1-Jan-14
ak-senate-class-ii-2014 25-Feb-14 51.4921956208518
ak-senate-class-ii-2014 22-Apr-14 49.4276015976854
al-senate-class-ii-2014 1-Jan-14
al-senate-class-ii-2014 25-Feb-14 9.22057393777991e-10
al-senate-class-ii-2014 22-Apr-14 4.14383203099536e-10
date dem
1-Jan-14 50
25-Feb-14 35
22-Apr-14 55
slug name
mark-begich Mark Begich
william-bryk William Bryk
john-jaramillo John Jaramillo
joe-miller Joe Miller
sarah-palin Sarah Palin
daniel-s-sullivan Dan Sullivan
kathleen-tonn Kathleen Tonn
mead-treadwell Mead Treadwell


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