Advancing UN Comtrade for Physical Trade Flow Analysis: Addressing the Issue of Outliers

•Outliers exist in UN Comtrade for almost all reporters (207 in 209), all commodities, and all years.•Most outliers (92% of the total) are with wrong net weight values.•Outliers may be few in numbers but cause significant biases in physical trade flow analysis.•Based on potential causes, our outlier handling could retain most critical information.•Addressing the outlier issue would improve UN Comtrade quality and benefit related analysis.