Ernst Louis Étienne Laspeyres, 1834-1913, was a German economist, statistician and Professor in various universities. His most notable contribution to economics was the development of the Laspeyres index, used for the formulation of weighted indexes, so that each product that are included in them, have their own weight according to their real importance in the production, consumption, etc. He wrote about it in his “Die Berechnung einer mittleren Warenpreissteigerung”, 1871.
Laspeyres also wrote quite an amount of papers in the fields of economic history, the history of economic thought and on economic issues concerning his time.
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