A measure of the loss caused by an output level at which marginal cost and marginal benefit are not equal. In a market with an upward-sloping supply curve and a downward-sloping demand curve, if output is below the level at which the curves intersect, the triangle of loss is the area between actual output and the output at the intersection above the supply curve and below the demand curve. If the units between the actual and the intersection had been produced the marginal benefit to consumers would have been greater than the cost to producers. If output is above the equilibrium level, the triangle of loss is the area between equilibrium and actual output above the demand curve and below the supply curve. If these units are produced, the marginal benefit to consumers is less than the cost to producers. See also deadweight loss; Harberger triangle.