Party policy equilibrium for alternative spatial voting models: An application to the Norwegian Storting

In recent years a lively debate has emerged concerning the empirical status of the traditional proximity spatial model versus a directional model of v oter choice. The central reason for this scholarly interest concerns these models' contrasting implications for parties' policy positioning, with the directional model motivating parties to present extreme policies, but the p roximity model promoting centrist positions. To this point, however, there exist no studies that compute parties' optimal strategies in historical ele ctions, for these competing models. This article addresses this issue, by e xamining party policy strategies in a multiparty electorate for three diffe rent vote models: (a) the proximity model, (b) a directional model (c) a mi xed model which combines proximity and directional components. Each model i ncorporates past voting history and the random effects of unmeasured variab les. Using parameter estimates derived from analyses of survey data from th e 1989 Norwegian Election Study we compute - for each of these vote models - the configuration of party policy positions that maximize each party's vo te share in relation to those of the other parties. We find that for each m odel, such a vote-maximizing configuration exists, but - for the proximity model - represents an unrealistic, tightly clustered array. A mixed proximi ty-directional model, however, provides by far the most convincing account of parties' actual policy strategies with regard to dispersion and vote sha re.