This paper uses new product-specific, micro-level US data to show that New England had lower levels of productivity in cotton spinning than Lancashire, c. 1900, contradicting results derived by Broadberry from the Censuses of Production. The discrepancy stems from the Censuses’ poor methods of aggregating heterogeneous yarn output. The finding that Britain – the labour-abundant country – has higher labour productivity contradicts the Rothbarth-Habakkuk model. We suggest Britain’s industrial success stems from more intensive competition, manifested through external economies of scale and longer production runs. We finish with some speculative implications for British performance in the first and second industrial revolutions