📌 What This Study Does

This article proposes a new, more objective way to classify political parties and applies that method to Brazil, focusing on the election results of small parties. It aims to contribute to the literature on party systems by improving how party size is measured for comparative and descriptive analysis.

📊 How Party Size Was Measured

Cluster analysis is used to classify party size based on each party’s percentage of votes across Brazilian states. This empirical, vote-share–based clustering replaces prior, more ad hoc classifications.

🔍 Key Findings

• Classifying parties through cluster analysis produces a more objective grouping than previous classifications.
• Small parties exert little effect on electoral volatility in Brazil.
• Small parties benefit less from the disproportionality between votes and seats than larger parties.

⚖️ Why It Matters

The clustering method offers a transparent, data-driven tool for scholars studying party systems and electoral dynamics. Applied to Brazil, the results suggest that small parties play a limited role in driving volatility and reap fewer advantages from vote–seat disproportionality than larger parties, which has implications for debates about fragmentation and representation.