CIS - Centro de Investigaciones Sociológicas

The Inertia-Uncertainty Bifactor Model is an analytical tool designed at the Center for Sociological Research to measure the electoral support, both determined and potential, that political parties may receive at the time of data collection. Based on the application of the scenario method, it specifies a set of multiple potential realities resulting from a combination of theoretically significant factors. The model estimates the probabilities of voting for each political party in each of the scenarios.

This text demonstrates the application of the Bifactor Model, for diagnostic purposes, in the 2024 Galician regional elections. Its purpose is not to estimate votes, which is only one of its capabilities, but rather to illustrate its functionality for exploring the different configurations of partisan competition according to the electorate's decision-making process. To this end, after a brief introduction to the model's theoretical foundations, the voting configurations are explored for two segments: decided voters and voters in the process of deciding. This exploration was carried out using surveys at three different times: pre-election survey (Study E3437), pre-campaign survey (Study E3440), and campaign survey (Study E3442). The model allows for the study, among other elements, of changes in the electoral strength correlations of the different parties at each stage of the decision-making process, as well as the interdependencies between electorates, the effects of turnout on each party, the asymmetric effects of uncertainty, and the degree of local fragmentation of the electorates. For example, strong volatility is observed among the Popular Party's electorates, which tend to reduce their uncertainty as the election date approaches. This is partly explained by the shift in their campaign, which incorporated the confrontation with the BNG and the independence movement as a central theme.

In this sense, this text exemplifies how estimates from the Bifactor Model can be used to understand the process by which electoral results were reached.

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