Robust Ideal Point Estimation with L0 Regularization
Analysis
This paper addresses a critical problem in political science: the distortion of ideal point estimation caused by protest voting. It proposes a novel method using L0 regularization to mitigate this bias, offering a faster and more accurate alternative to existing methods, especially in the presence of strategic voting. The application to the U.S. House of Representatives demonstrates the practical impact of the method by correctly identifying the ideological positions of legislators who engage in protest voting, which is a significant contribution.
Key Takeaways
- •Addresses the problem of protest voting in ideal point estimation.
- •Proposes an L0-regularized Item Response Theory model.
- •Demonstrates improved accuracy and speed compared to existing methods.
- •Provides a method for identifying protest votes.
- •Applies the method to the U.S. House of Representatives, correcting misclassifications.
“Our proposed method maintains estimation accuracy even with high proportions of protest votes, while being substantially faster than MCMC-based methods.”