Candidate Ideology and Electoral Outcomes in the 2018 U.S. House of Representatives Election: Evidence from Primary Elections and Twitter Ideal-Point Data Open Access

Hicks, Jacob (Spring 2020)

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How does candidate ideology affect electoral success? This seemingly simple question has led to countless books, articles, and other publications. This thesis explores the use of Twitter-based ideology measures developed by Dr. Pablo Barbera. Using a unique dataset comprising 1,212 candidates in the 2018 U.S. House of Representatives Election, I conduct an analysis of electoral outcomes on a scale not previously possible. My results suggest that when compared to the ideology of the primary electorate in which they compete, candidate ideology is not a reliable predictor of success in primary elections. The use and validation of Dr. Barbera’s measure of candidate ideology is a significant contribution and further analysis in this area will allow for expanded study of primary elections. Furthermore, this data is a promising avenue for future research into the impact of candidate ideology on electoral outcomes.

Table of Contents

1 Introduction and Research Question 1

2 Literature Review 2

3 Theory 7

3.1 Model 11

3.2 Hypothesis 11

4 Methods 12

4.1 U.S. House of Representatives 12

4.2 Measuring Electoral Success 14

4.3 Measuring Candidate Ideology 14

4.4 Measuring Ideological Distance 15

4.5 Controls 17

4.6 Analysis 18

4.7 Comparisons and Establishing Viability 18

4.8 Data Collection 19

5 Results 20

6 Discussion 23

7 Conclusion 24


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