The Causes of Rising Opinion Dissensus on Taiwan's Constitutional Court

Abstract

Defined as the non-unanimity of judicial opinion as recorded by individual judges’ concurrences and/or dissents, the opinion dissensus on Taiwan’s Constitutional Court (TCC) has risen steadily and markedly in the past decade or so. What drives the Justices of TCC to write separately, and what has turned more Justices into frequent opinionators? This paper looks into the possible causal explanations of this intriguing phenomenon, and subjects them to empirical testing. We utilize two case-based measures — Concurrence Score (CS) and Dissent Score (DS) — as our dependent variables, and we identify and assess 16 independent variables in four categories: demographics, composition diversity, agenda (case-specific), and institutional and collegial. The findings of our multiple regression analysis demonstrate that opinion dissensus on TCC has been shaped by a multitude of factors. In particular, we found a linkage between the rise of opinion dissensus on TCC since the mid-2000s and the 2003 institutional change regarding the term of the Justiceship, which has henceforth increased the composition diversity of the Court.

Keywords: Taiwan’s Constitutional Court, opinion dissensus/consensus, concurrence, dissent, composition diversity, diversity indices