Party system fragmentation, social cleavages, and social media: New Zealand’s 2017 election campaign on Facebook

ABSTRACT Explorations of the predictive relationship between party system fragmentation and social cleavages beyond a single dimension remains an undeveloped area of research, one which rarely accounts for the changing technological landscape where parties now compete. This case study of New Zealand's 2017 election campaign on Facebook contributes to this area. It reveals an environment where parties compete within social cleavages for support, and users demonstrate a diverse preference for cleavage appeals. The findings also offer a compromise between the competing theories about New Zealand’ social cleavage structure. Finally, we revisit the predictive relationship between party system size and social cleavages in a postdictive fashion, demonstrating the continued explanatory power of cleavage structure, this time with data derived from social media.