3:1 Nesting Rules in Redistricting
share
In legislative redistricting, most states draw their House and Senate maps separately. Ohio and Wisconsin require that their Senate districts be made with a 3:1 nesting rule, i.e., out of triplets of adjacent House districts. We seek to study the impact of this requirement on redistricting, specifically on the number of seats won by a particular political party. We compare two Markov Chain Monte Carlo simulations, one which uses the ReCom chain to generate Senate maps without a nesting requirement, and the other which uses a novel chain that generates Senate maps with a 3:1 nesting requirement. Moreover, we implement Ohio's constitutional county splitting requirements in both chains. We find that requiring a 3:1 nesting rule has minimal impact on the distribution of seats won. On the other hand, enforcing Ohio's county splitting requirements severely restricts this distribution.
READ FULL TEXT