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How Much Influence Do Opinion-Writers Have on Per Curiam Courts? Uncovering Author Drift in Written Decisions at the European Court of Justice

Published online by Cambridge University Press:  10 July 2026

Sivaram Cheruvu*
Affiliation:
Michigan State University, United States
Jeffrey Ziegler
Affiliation:
Trinity College Dublin, Ireland
*
Corresponding author: Sivaram Cheruvu; Emails: cheruvus@msu.edu
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Abstract

Research that assesses individual judges’ ability to shape decisions typically focuses on courts that publish separate votes and opinions. Yet, many courts issue per curiam judgments that do not permit public dissent. To overcome this limitation, we use a convolutional neural network (CNN) to model the variation in judges’ expressed preferences from language in aggregated judgments. Specifically, we construct a CNN to analyze the written judgments of judge-rapporteurs and opinions of advocates-general from the Court of Justice of the European Union. Along a pro-/anti-EU dimension, we estimate how judgments differ within (1) each case relative to the advocate-general’s opinion, and (2) each judge-rapporteur, which captures how judges alter their writing across cases. Our results provide novel empirical support for theoretical models of European judicial decision-making: more pro-EU opinions driven by the Court, not the advocate-general or the judge-rapporteur, are associated with larger chambers and stronger external signals of compliance.

Information

Type
Research Article
Creative Commons
Creative Common License - CCCreative Common License - BY
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.
Copyright
© The Author(s), 2026. Published by Cambridge University Press on behalf of the Law and Courts Organized Section of the American Political Science Association
Figure 0

Table 1. Estimated Association of Case Factors with (1) Within-case i Drift of JR from AG and (2) Within-rapporteur Drift between Case i and Rapporteur k AverageTable 1. long description.

Figure 1

Figure 1. Marginal effect of member states’ observations on direction of drift from the AG’s position varying panel size.Note: 95% confidence intervals are displayed in light gray ribbons, and the observed frequency density of the moderator is shown along the x-axis. The full table of estimated coefficients can be found in the Supplemental Information.Figure 1. long description.

Figure 2

Figure 2. Mean predicted value of paragraphs from AG opinion and judgment.Note: The observed average mean predicted value of each paragraph along the pro-/anti-EU dimension is displayed along the x-axis. The ribbons around the predicted probabilities represent the mean 2.5% and 97.5% values (i.e., 95% credible intervals) from the 100 draws of the CNN posterior distribution. Values closer to zero represent more anti-EU statements, while values closer to one indicate more pro-EU sentiments. The color and shape of the points correspond to the section of the judgment or AG opinion in which each paragraph is presented. Each paragraph is shown sequentially along the y-axis.Figure 2. long description.

Supplementary material: File

Cheruvu and Ziegler supplementary material

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Cheruvu and Ziegler Dataset

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