Quantifying Bias from Measurable and Unmeasurable Confounders Across Three Domains of Individual Determinants of Political Preferences

Rafael Ahlskog,Sven Oskarsson

doi:10.1017/pan.2022.2

Abstract

AbstractA core part of political research is to identify how political preferences are shaped. The nature of these questions is such that robust causal identification is often difficult to achieve, and we are not seldom stuck with observational methods that we know have limited causal validity. The purpose of this paper is to measure the magnitude of bias stemming from both measurable and unmeasurable confounders across three broad domains of individual determinants of political preferences: socio-economic factors, moral values, and psychological constructs. We leverage a unique combination of rich Swedish registry data for a large sample of identical twins, with a comprehensive battery of 34 political preference measures, and build a meta-analytical model comparing our most conservative observational (naive) estimates with discordant twin estimates. This allows us to infer the amount of bias from unobserved genetic and shared environmental factors that remains in the naive models for our predictors, while avoiding precision issues common in family-based designs. The results are sobering: in most cases, substantial bias remains in naive models. A rough heuristic is that about half of the effect size even in conservative observational estimates is composed of confounding.

Highlights

The last decades have seen a steady rise, across the social sciences, in the interest in methods for robust causal inference (Angrist and Pischke 2010; Clark and Golder 2015)
The purpose of this paper is to measure the magnitude of bias stemming from both measurable and unmeasurable confounders across three broad domains of individual determinants of political preferences: socio-economic factors, moral values, and psychological constructs
The purpose of this paper is to attempt to measure the magnitude of bias stemming from both measurable and unmeasurable confounders for three broad and well-established domains of individual determinants of political preferences: socioeconomic factors, moral values, and psychological constructs

Summary

Introduction

The last decades have seen a steady rise, across the social sciences, in the interest in methods for robust causal inference (Angrist and Pischke 2010; Clark and Golder 2015). A growing number of studies have documented that just like other human traits (Polderman et al 2015) individual variation in political behavior is to some degree influenced by genetics (Alford, Funk, and Hibbing 2005; Hatemi et al 2014). This raises the spectre of genetic confounding: traits might be correlated because they are influenced by the same genetic architecture. Expensive, for example, where income and wealth are concerned

Objectives

Methods

Results

Conclusion