Description of Equation 3: Labour productivity LP is defined here as output per unit of labour input. Output is measured using GDP calculated at basic prices. Labour input H is measured using hours worked. Hours worked for Canadian small-sized businesses are re-calculated using the U.S. shares of hours worked for small and large-sized businesses. The Canadian labour productivity of industry i is the weighted average of the labour productivity in the small and large business size categories j for industry i, where the weights are a share of U.S. hours for each business-size category in industry i. The U.S. labour productivity follows equation (1) and (2).