How Polarised are Citizens? Measuring Ideology from the Ground up

We investigate whether the ideological polarisation of citizens has increased in Western democracies. We propose a novel methodology to identify individual ideologies by applying latent Dirichlet allocation to political survey data. This approach indicates that questions related to confidence in institutions play a leading role in defining citizen ideologies, in addition to the questions associated with the traditional left-right scale. We decompose the shift in ideological positions across the population over time and measure polarisation. This reveals evidence of a ‘disappearing centre’ in a sub-group of countries with citizens shifting away from centrist ideologies into anti-establishment ‘anarchist’ ideologies. This trend is especially pronounced for the United States.