Production and Costs $ $ $ Microeconomics - Dr. D. Foster Supply side of the market Why firms exist. Production and cost relationships. Model of perfect competition. Model of monopoly. Regulation Later: Monopolistic competition, oligopoly, game theory, factor markets, general equilibrium Why do firms exist? They combine resources to produce goods and services. Why not use markets? Transaction costs are high. Role of managers - monitor workers to minimize shirking. Chinese barge-pullers. Firm’s objective: maximize profit Costs & Profits All costs are “opportunity costs.” Costs may be explicit or implicit. Total cost = TC = all relevant costs. (Economic) Profit = TR-TC – If positive, firms will enter. – If negative, firms will exit. – If zero, the market is stable. Accounting profit may/will not equal Economic Profit. $ Short Run vs. Long Run We are interested in the short run: At least one input is fixed Fixed - capital; variable – labor In the Long Run, all factors are variable. Next - Production & Cost relationships Production Relationships Output Total Product = TP (=Q) Labor L1 L3 From 0 to L1 there are “increasing returns.” From L1 onwards, there are “diminishing marginal returns.” After L3 additional workers lower output. Why? Production Relationships Output Marginal Product = MP TP (=Q) Average Product = AP Labor L1 L2 L3 Marginal Product = MP = ΔTP/ΔL; this shows how much the last worker (unit) adds to output. Average Product = AP = TP/L; this shows how much the average worker adds to output. Cost Relationships $ As noted, TC = TFC + TVC TFC is fixed, by definition. TVC can be written as w*L, where w is the (constant) wage rate. Average Fixed Cost, AFC = TFC/Q Average Variable Cost, AVC = TVC/Q . . . or, = wL/Q = w/AP As AP rises, AVC falls . . . Average Total Cost, ATC = TC/Q = AFC + AVC Cost Relationships $ Marginal Cost, MC = ΔTC/ΔQ or, can be written as = ΔTVC/ΔQ (Why?) … = Δ(wL)/ΔQ = w(ΔL)/ΔQ = w/MP $ MC ATC AVC AFC quantity (TP) Complete the Production and Cost Worksheets Key Formulas MP = ΔTP/ΔL AP = TP/L TC = TFC + TVC TVC = w*L AFC = TFC/Q AVC = TVC/Q = wL/Q = w/AP ATC = TC/Q = AFC + AVC MC = ΔTC/ΔQ = ΔTVC/ΔQ = Δ(wL)/ΔQ = w(ΔL)/ΔQ = w/MP $ Production and Costs $ $ $ Microeconomics - Dr. D. Foster