Illinois House / Illinois Senate
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2020 Election Update
Heading into the 2020 election, Democrats controlled the Illinois Senate 40 to 19. Democrats flipped one seat (SD 25) for a net gain of one seat. Democrats now control the chamber 41 to 18.
The below table shows 2020 and 2018 election results for the Illinois Senate. The LDI scores are for the 2020 cycle. EveryDistrict will release new scores and district rankings after the redistricting process.
2018 Election Update
After the 2016 election, Democrats controlled the Illinois State Senate 37-22. In the 2018 election, Democrats flipped three seats to grow their majority to 40-19.
Democrats flipped SD 21, SD 24, and SD 27.
Understanding the Map
EveryDistrict’s Legislative District Index (LDI) is the gold standard of state legislative competitiveness. Our LDI ranks state legislative districts on a scale from 100 to -100, using statewide elections data. Districts with a score of 100 would vote for statewide Democratic candidates by an average of 100 points (with the Democratic candidate receiving 100% of the vote); districts with a score of -100 would vote for statewide Republican candidates by an average of 100 points (with the Republican candidate receiving 100% of the vote). For a more realistic example, a district with a score of 10 would vote for statewide Democratic candidates by an average of 10 points (meaning we would expect the Democratic state legislative candidate to win with 55% of the vote compared to the Republican winning 45% of the vote).
After the 2018 election, EveryDistrict reviewed and enhanced our LDI system, improving the accuracy of the metric with new methodologies and the most recent electoral data.
For more information about EveryDistrict’s LDI, please click here.