90%
Winning percentage of runoff candidates who finished 15% or more ahead of their challenger in the primary election, since 2002.
There have been 144 “open” primary runoff elections for statewide, legislative, Board of Education and federal offices since 2002 (“Open” means excluding an incumbent. We address them below.). In general, the candidate who received a plurality vote has won more often (61%) than the candidate playing from behind (39%). There have been strong variations to that overall trend based on two numbers from the primary: the plurality candidate’s share of the vote and the margin between that candidate and the other runoff candidate.
Since 2002, candidates receiving a plurality vote in excess of 40% have won 70% of their runoff races. Candidates whose plurality vote was 40% or less have gone on to win just 53% of the time. Historical runoff winning percentages wobble dramatically when the margin between the candidates is also considered:
- 82% of candidates with a plurality vote in excess of 40% and a margin of more than 10%
- 55% of candidates with a plurality vote in excess of 40% and a margin of 10% or less
- 87% of candidates with a plurality vote of 40% of less and a margin of more than 10%
- 45% of candidates with a plurality vote of 40% or less and a margin of 10% or less
Regardless of their initial share of the vote, candidates whose margin over the other runoff candidate is 2.5% or less have won just 38% of runoffs. As the initial stat indicated, 90% have won with an initial margin of 15% or more, regardless of their initial share of the vote.
Below, we break each 2018 runoff into the four bulleted groups. Remember that the percentages are not a prediction. They are merely the historical winning percentage of similarly situated leading candidates during the past eight election cycles.
More than 40% of primary vote, lead of more than 10%
82%
GOV DEM: Lupe Valdez (43-27)
SD17 DEM: Rita Lucido (49-35)
HD4 REP: Stuart Spitzer (46-26)
HD45 DEM: Rebecca Bell-Metereau (45-31)
HD107 REP: Deanna Metzger (45-27)
ED12 DEM: Suzanne Smith (48-26)
CD3 DEM: Lorie Burch (49.6-29)
CD6 REP: Ron Wright (45-22)
CD23 DEM: Gina Ortiz Jones (41-17)
CD27 DEM: Roy Barrera (41-23)
CD31 DEM: M.J. Hegar (45-34)
More than 40% of primary vote, lead of 10% or less
55%
HD8 REP: Cody Harris (45-39)
HD62 REP: Reggie Smith (46-34)
HD64 DEM: Mat Pruneda (42-39)
HD109 DEM: Deshaundra Lockhart Jones (45-40)
HD133 DEM: Sandra Moore (49.92-41)
40% or less of the primary vote, lead of more than 10%
87%
CD10 DEM: Mike Siegel (39.96-18)
CD21 REP: Chip Roy (27-17)
CD29 REP: Phillip Aronoff (39-24)
CD32 DEM: Colin Allred (39-18)
40% or less of the primary vote, lead of 10% or less
45%
HD13 REP: Jill Wolfskill (39-36)
HD46 DEM: Chito Vela (39.6-38)
HD47 DEM: Vikki Goodwin (34-29)
HD121 REP: Matt Beebe (29-26)
CD2 REP: Kevin Roberts (33-27)
CD5 REP: Lance Gooden (30-22)
CD6 DEM: Ruby Faye Woolridge (37-37)
CD7 DEM: Lizzie Pannill Fletcher (29-24)
CD21 DEM: Mary Wilson (31-29)
CD22 DEM: Sri Preston Kulkarni (32-24)
CD25 DEM: Chris Perri (33-26)
CD27 REP: Bech Bruun (36-34)
This analysis does not include runoffs in which an incumbent is one of the candidates. Historically, runoffs are not kind to incumbents. Just five out of the last 25 incumbents forced into runoffs have survived, including one out of three in 2016. No incumbent has won a runoff when they did not finish first in the primary election since 1992.
Two incumbents are in runoffs this year: Rep. Scott Cosper (R-Killeen) and Rep. Rene Oliveira (D-Brownsville). Both finished first in their respective primary elections. Four of the previous five incumbents who prevailed finished at least 17.5% ahead of their rivals in the primary. Oliveira finished 12% ahead of Alex Dominguez. Cosper finished just 3% ahead of Brad Buckley. Incumbents whose primary margin was 5% or less have won just once in the last seven such runoffs.
©2018 Texas Election Source LLC
