A major 2026 academic study (292 million trades, 327,000 binary contracts across Kalshi and Polymarket) reveals that prediction market calibration is not uniform — it is a structured, multidimensional phenomenon. Understanding these biases gives sophisticated Polymarket trading bots a massive, repeatable edge. Key Calibration Findings The paper decomposes calibration variance into four components explaining 87.3% of observed patterns on Kalshi (with strong replication on Polymarket): Universal H