The analysis measuring the "efficiency gap" shows Kentucky Republicans won about three more seats than they should have given their share of statewide votes. A similar analysis in 2014 showed Democrats had a slight advantage in the same districts.
Republicans won 64 out of 100 seats, giving them a majority for the first time in nearly 100 years.
Two researchers who developed the efficiency gap say Kentucky's results are, statistically speaking, not much different than zero. They said factors other than gerrymandering could have contributed, including shifting political attitudes.