Chapter 13: Aggregate Supply The Model The relationship between production of goods and services and the general price level Y = Y + α (P – Pe) Where – – – – Y = actual level of output Y = full-employment level of output P = actual price level Pe = expected price level Aggregate Supply Price level Long-run AS where P = Pe Short-run AS where P > or < Pe P Y Output, Income Sticky Wage Model Nominal wages are sticky downward They adjust to price changes slowly Demand for Labor: Ld = L(W/P) Production Function: Y = F(L,K) As price (P) increases, the real wage (W/P) falls, firms respond by hiring more labor (L) and producing more output (Y) Sticky Wage Model Real Wage Y1 Output Y2 W/P1 W/P2 Y Ld L1 L2 Labor L1 L2 Price P2 P1 Labor Short-run AS Y1 Y2 Output Workers Misperception Model Workers confuse nominal “wage” changes with “real” wage changes when the price level changes unexpectedly Demand for Labor: Ld = L(W/P) Supply for Labor: Ls = L(W/Pe) Write the “expected” real wage as W/Pe = W/P * P/Pe As P increases, W/P declines but P/Pe increases Workers confuse the real wage decline with a nominal wage increase, hence supplying more labor services Workers Misperception Model Real Wage Price Ls1 Short-run AS Ls2 P2 W/P1 P1 W/P2 Ld L1 L2 Labor Output Y1 Y2 Imperfect Information Model Firms track price changes of their own product more closely than changes of the general price level Perceptions of an increase in the “relative” price level causes the labor demand, employment, and output to rise Let PW = price of wheat and P = general price level With inflation, farmers perceive Pw/P is increased, hence hiring more labor and producing more output Imperfect Information Model Real Wage Ls W/P2 W/P1 Y1 Output Y2 Y Ld2 Ld1 L1 L2 Labor Price L1 L2 Labor Short-run AS PW2 PW1 Y1 Y2 Output Sticky Price Model Two kinds of firms: – Flexible-price firms: those with market power to adjust their prices in response to market changes p = P + α (Y – Y) – Fixed-price firms: those with no market power, hence unable to adjust their prices p = Pe Sticky Price Model The general price level is the “weighted” average price charged by the flexible-price and fixed-price firms P = sPe + (1-s)[P + α (Y – Y)] Here s is the market share of the fixed-price firms and (1-s) is the market share of the flexible-price firms Sticky Price Model The aggregate supply curve is: Y = Y + α’ (P – Pe) Where α’ = s / α(1-s) Shift in Aggregate Demand Assume the AD rises due to greater expenditures in the economy, increasing the level of price and output People adjust their expectations for higher prices A higher expected price level results in a lower expected real wage The supply of labor declines, reducing the AS and the level of output Long-run equilibrium is achieved at the natural level of output, but a higher price level Shift in Aggregate Demand Price level Long-run AS C P3 P2 P1 SRAS2 SRAS1 B A AD2 AD1 Y Y1 Output, Income The Phillips Curve The relationship between inflation rate and unemployment rate, In the short-run: π = π* - β(u- u*) + v π = actual inflation rate π* = expected inflation rate u = actual unemployment rate u* = natural unemployment rate v = cost-push factor β = the output adjustment factor The Phillips Curve There is a “trade-off” between inflation and unemployment In the long-run, u = u* and v = 0, so π = π*: no trade-off between inflation and unemployment Stagflation is depicted by a shift of the Phillips Curve, resulting in higher unemployment and inflation Shift of the Phillips Curve Inflation Rate π2 π1 B P2 A u1 P1 u2 Unemployment Rate