The impact of agricultural policy distortions on the productivity gap: Evidence from rice production

► New crop productivity index using a different dynamic panel model was constructed. ► Indexes showed the gap in rice productivity between rich and poor countries widened. ► Rich countries subsidized while poor countries taxed their rice production and export. ► An econometric model linking productivity gap to policy distortions was presented. ► Rich countries' subsidies, protection and poor countries' tax widened productivity gap.