Although most scholars acknowledge that district-level election results are compositional variables, few model them as such. Instead, they tend to model the shares of single parties across districts, because of partial contestation (situations where not all parties field candidates in every electoral district). We advance the current framework on the compositional modelling of electoral contestation to include a sample-selection approach similar to Heckman’s and an intuitive approach that involves explicitly controlling for whether a party contests a particular district. We test these approaches against established compositional approaches using both simulated and real-world data.