Bartle, Stimson and Dellepiane-Avellaneda (2010) show that British public opinion moves against whoever is in government. However, in Scotland there are two governments. This paper addresses two questions: Firstly, do shifts in Scottish public opinion tracks those in the UK as a whole, against the (Westminster) government of the day; and secondly are divergences in public opinion associated with changes in support for independence.
The paper is innovative in its measurement of policy mood and support for independence. It uses Bayesian Item Response Theory (McGann 2013) to produce a consistent measure of left-right policy mood and support for independence. We refine these methods to allow us to estimate support for independence despite the fact that some questions provide two options and others three. Drawing from pseudo-panel data, we estimate the characteristics of each questions asked and use this to track the movements over time of subsets of the population.
