Waseda Uni



The University of Essex and Waseda University (Centre for Empirical Analysis of Political Economy, Top Global University project) will co-organise the Essex Summer School (ESS) at Waseda University this summer. ESS will offer the course, Scaling Methods and Ideal Point Estimation (18-26 September) with Professor Royce Carroll.

The number of seats will be limited to up to 30 students.

The prerequisites for taking this course are:
To have already learned the basics of regression analysis (e.g. least squares method) (regardless of their academic affiliation or university)
Basic understanding of the statistical language R (e.g. manipulating data frames, reading and writing files, creating functions)

The course is aimed at graduate students, but are also open to undergraduate students.

The course will be taught in English.

The tuition fee for the course is £200.

Upon the completion of the course, Essex University will issue formal certification.

Application deadline: 28 August 2023

Please note:
• Students are required to make their own accommodation and travel arrangements.
• Waseda cannot sponsor a student visa.



Scaling Methods and Ideal Point Estimation

Royce Carroll is a Professor in Comparative Politics at the University of Essex. His research focuses on representation and legislative politics, as well as methods to analyse survey and voting data, attitudes, preferences and ideology. He has previously taught at Rice University. He is co-author of the scaling method textbook Analysing Spatial Models of Choice and Judgment (2nd Ed. 2020), as well as many articles on related topics.

Course Content:
This course focuses on methods to discover, understand and visualize latent patterns in data and is especially suited to students with projects using survey data and other forms of relational data used in political science, sociology, economics, business, marketing, and psychology. The course introduces students to measurement theory and methods of scaling techniques, integrating Multidimensional Scaling, Item Response Theory, and Ideal Point Estimation. The first part of the course will provide an overview of the foundations of these techniques and introduce students to the most common methods for scaling and “spatial” analysis and the visualization of latent patterns in survey and behaviour data. The course will demonstrate how to interpret, measure, and visualize latent dimensions of data via a variety of scaling methods using the open-source programming language R. The course will also discuss a range of applications these methods to social science studies of relational and perception data derived from elite behaviour and surveys, especially for identifying latent preferences of political, economic and social actors. The course concludes with discussions of the most recent advances in the field, including applications for text analysis, and practical advice for those seeking to use such methods in social science research, relevant to the students enrolled. The course first covers how to analyse data from scales found in surveys (such as Likert-type scales), focusing on surveys that ask respondents to place themselves and / or stimuli on issue or attribute scales. The course begins with approaches to scaling to generate bias-adjusted and latent spatial data from survey responses, such as the Aldrich-McKelvey scaling and ‘Basic Space’ scaling with Anchoring Vignettes as methods for addressing perceptual bias in the form of “Differential Item Functioning.”  The course next examines similarities and dissimilarities data and covers multidimensional scaling (MDS) with a focus on the SMACOF optimization method implemented in R as well as Bayesian applications to Metric Multidimensional Scaling. Next, the course covers unfolding analysis of rating scale data from surveys such as favourability scales for stimuli such as politicians or social groups. Finally, the course provides an extensive overview of IRT and ideal point estimation, generally focused on binary choice data, which includes those used in ‘roll call voting’ analysis of elite behaviour in parliaments and courts. Here we will cover Poole and Rosenthal’s W-NOMINATE and Poole’s Optimal Classification unfolding method, as well as a variety of Bayesian analysis techniques for binary and ordinal choice data using Item Response Theory (IRT). An extensive range of Bayesian techniques is discussed, including Bayesian Aldrich-McKelvey Scaling, Ordinal and Dynamic Item Response Theory (IRT), Bayesian Multidimensional Scaling (MDS), and Bayesian Unfolding. The final section will discuss recent methods for scaling to a variety of different data types, including social media and text data, and the latest computation innovations to apply scaling methods to ‘big data’.

This course will enable students to derive latent spatial preference information and/or a dimensional structure from various types of survey and behavior data, which is applicable to a wide range of social science applications, academic and non-academic alike. Consumers of research based on these methods will also benefit from a deeper understanding of this type of methodology, its potential and its limitations.

Course Objectives:
Students will learn to use various computational methods to generate measures of ideology and preferences and understand the latent dimensional properties of social science data, including surveys and legislative data. Students will understand the theories behind these methods and the relationships between Item Response Theory, Ideal Point Estimation and other scaling methods. As these techniques are fundamental parts of much recent work in social science, students will be able to both understand and produce this research based on measuring concepts in this way.

Course Pre-requisites:
The course is designed to be accessible to social science graduate students of all backgrounds. However, students familiar with the R programming environment will find it easier to adapt to course content and assignments, so it is recommended to familiarize oneself with the basic structure of R/Rstudio, such as via the 1-day introduction to R offered the Sunday before the first day of class. In addition, the course assumes basic familiarity with general statistics (OLS and MLE).


Armstrong, David A and Bakker, Ryan and Carroll, Royce and Hare, Christopher and Poole, Keith T and Rosenthal, Howard (2014) Analyzing spatial models of choice and judgment with R. Chapman and Hall/CRC. ISBN: 9781138715332 (electronic copy will be provided by instructor)

Background knowledge required:

OLS = elementary

Maximum Likelihood = elementary

R = elementary