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Chapter 11. Spending and Output in the Short Run. Learning Objectives. Identify the key assumptions of the basic Keynesian model Discuss the determination of planned investment and planned aggregate expenditure
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Chapter 11 Spending and Output in the Short Run
Learning Objectives • Identify the key assumptions of the basic Keynesian model • Discuss the determination of planned investment and planned aggregate expenditure • Analyze how an economy reaches short-run equilibrium in the basic Keynesian model • Show how a change in planned aggregate expenditure can cause a change in the short-run equilibrium output
Keynesian Model Key assumption: • In the short run, firms meet demand at preset prices • Firms typically set a price and meet the demand at that price in the short run • Eventually, firms change prices when the marginal benefits exceed the marginal costs • Basic Keynesian model developed here ignores this fact.
Planned Aggregate Expenditure • Planned aggregate expenditure is planned spending on final goods and services • Four components of planned aggregate expenditure • Consumption (C) by households • Investment (I) is planned spending by domestic firms on new capital goods • Government purchases (G) are made by federal state and local governments • Net exports (NX) is exports minus imports
Planned Investment Example • Fly-by-Night Kite produces $5 million of kites per year • Expected sales are $4.8 million and planned inventory increase is $0.2 million • Capital expenditure of $1 million is planned • Planned investment is $1.2 million • If actual sales are only $4.6 million • Unplanned inventory investment of $0.2 million • Actual investment is $1.4 million • If actual sales are $5.0 million • Unplanned inventory decrease of $0.2 million • Actual investment is $1.0 million
Planned Aggregate Expenditure (PAE) • Actual spending equals planned spending for • Consumption • Government purchases of final goods and services • Net exports • Adjustments between actual and planned spending are accomplished with changes in inventories • The general equation for planned aggregate expenditures is PAE = C + IP + G + NX
Consumption Expenditures • Consumption (C) accounts for two-thirds of total spending • Powerful determinant of planned aggregate spending • Includes purchases of goods, services, and consumer durables, but not houses • Rent is considered a service • C depends on disposable income, (Y – T)
Consumption Function • The consumption function is an equation relating planned consumption to its determinants, notably disposable income (Y – T) C = C + (mpc) (Y – T) where C is autonomous consumption spendingmpc is the change in consumption for a given change in (Y – T) • Autonomous consumption is spending not related to the level of disposable income • A change in C shifts the consumption function
Consumption Function C = C + (mpc) (Y – T) • C captures wealth effect • The effect of changes in asset prices on consumption spending • C also captures the effects of interest rates on consumption • Higher rates increase the cost of using credit to purchase consumer durables and other items
More Consumption Function C = C + (mpc) (Y – T) • Marginal propensity to consume (mpc) is the increase in consumption spending when disposable income increases by $1 • mpc is between 0 and 1 for the economy • If households receive an extra $1 in income, they spend part (mpc) and save part • (Y – T) is disposable income • Output minus net taxes
Consumption Function C = C + (mpc) (Y – T) C Intercept slope Consumption spending (C) Δ C C Δ (Y – T) Slope = Δ C / Δ (Y – T) Disposable income (Y – T)
Planned Spending Example PAE = C + IP + G + NX C = C + mpc (Y – T) PAE = C + mpc (Y – T) + IP + G + NX • Suppose that planned spending components have the following values PAE = 620 + 0.8 (Y – 250) + 220 + 330 + 20 PAE = 960 + 0.8 Y
Planned Spending Example C = 620 + 0.8 (Y – 250) PAE = 960 + 0.8 Y • If Y increases by $1, C will increase by $0.80 • PAE increases by 80 cents • Planned aggregate expenditure has two parts • Autonomous expenditure, the part of spending that is independent of output • $960 in our example • Induced expenditure, the part of spending that depends on output (Y) • 0.8 Y in our example
Planned Expenditure Graph PAE = 960 + 0.8Y Planned aggregate expenditure (PAE) 960 Slope = 0.8 4,800 Output (Y)
Short-Run Equilibrium • Short-run equilibrium is the level of output at which planned spending is equal to output • Our equilibrium condition can be written Y = PAE • Using our previous example, PAE = 960 + 0.8 Y Y = 960 + 0.8 Y 0.2 Y = 960 Y = $4,800
Short-Run Equilibrium Graph Y = PAE PAE = 960 + 0.8Y Slope = 0.8 Planned aggregate expenditure (PAE) 960 45o 4,800 Output (Y)
Output Greater than Equilibrium • Suppose output reaches 5,000 • Planned spending is less than total output • Unplanned inventory increases • Businesses slow down production • Output goes down Y = PAE PAE = 960 + 0.8Y PAE 960 45o 4,800 5,000 Output (Y)
Output Less than Equilibrium • Suppose output is only 4,500 • Planned spending is more than total output • Unplanned inventory decreases • Businesses speed up production • Output goes up Y = PAE PAE = 960 + 0.8Y PAE 960 4,700 4,800 Output (Y)
Lower Equilibrium Y = PAE PAE = 960 + 0.8Y PAE = 950 + 0.8Y E Planned aggregate expenditure (PAE) F 960 950 Recessionary gap 45o 4,800 4,750 Y* Output Y
New Equilibrium – • Autonomous consumption, C, decreases by 10 • Causes a downward shift in the planned aggregate expenditures curve • The economy eventually adjusts to a new lower level of equilibrium spending an output, $4,750 • Suppose that the original equilibrium level, $4,800, represented potential output, Y* • A recessionary gap develops • Size of the recessionary gap is 4,800 – 4,750 = $50 • Entire decrease is in Consumption spending • Same process applies to a decrease in IP, G, or NX
Japan's Recession and East Asia • Japanese recession in 1990s reduced Japanese imports • East Asian economies developed by promoting exports • The decrease in exports to Japan decreased planned aggregate expenditures in these countries • The decrease in planned spending caused the economies to contract to a new, lower level of planned spending and output • Japan exported its recession to its neighbors • US recessions have similar effects on our major trading partners
Income-Expenditure Multiplier • The income – expenditure multiplier shows the effect of a one-unit increase in autonomous expenditure on short-run equilibrium output • Previous example • Initial planned expenditure = 960 + 0.8 Y • New planned expenditure = 950 + 0.8 Y • Equilibrium changed from $4,800 to $4,750 • A $10 change in autonomous expenditures caused a $50 change in output • Multiplier = 5
Stabilization Policy • Stabilization policies are government actions to affect planned spending with the intention of eliminating output gaps • Expansionary policies increase planned spending • Contractionary policies decrease planned spending • Two major stabilization tools are fiscal policy and monetary policy • Fiscal policy uses changes in government spending, transfers, or taxes • Monetary policy uses changes in the money supply
Government Spending • Government spending is part of planned spending • Changes in government spending will directly affect planned aggregate expenditures • Suppose planned spending decreases $ 10 from Y = 960 + 0.8 Y to Y = 950 + 0.8 Y • Equilibrium Y decreases from $4,800 to $4,750 • Recessionary gap is $50 • Stabilization policy indicates a $10 increase in government spending will restore the economy to Y* at $4,800
$10 Fiscal Stimulus Y = PAE PAE = 960 + 0.8Y PAE = 950 + 0.8Y E Planned aggregate expenditure (PAE) F 960 950 45o 4,800 4,750 Y* Output Y
Japanese Spending • In the 1990s Japan spent over $1 trillion on public works • Highways, subways, and transportation projects • Concert halls • Re-laying cobblestone sidewalks • Projects did not end the recession • Prevented larger decrease in income • Eroded consumer confidence because there was little demand • Consumers reduced spending in anticipation of higher taxes in the future
Taxes and Transfers • Planned aggregate expenditures are affected by taxes and transfers • The effect is indirect, channeled through the effects on disposable income • Lower taxes or higher transfers increase disposable income • Increases in disposable income lead to higher C
Tax Cuts Stimulate – An Example • Original planned spending PAE = 960 + 0.8 Y • Autonomous consumption, C, decreases by 10. Recessionary gap is $50. PAE = C + 0.8 (Y – T) + IP + G + NX • Tax cut to close the gap must be bigger than $10 • Increase disposable income to cause initial increase in spending to be $10 • Taxes will have to go down by $12.5
Chapter 23Appendix A An Algebraic Solution of the Basic Keynesian Model
The Basic Keynesian Model PAE = C + IP + G + NX C = C + mpc (Y – T) • The consumption function is defined by • C, autonomous consumption • mpc, the marginal propensity to consume, a number between 0 and 1 • IP, G, T and NX are given – – – –– –
Find Short-Run Equilibrium Output – – – – –– PAE = C + mpc (Y – T) + I + G + NX PAE = C – mpc T + I + G + NX + mpc Y • Equilibrium condition is PAE = Y Y = C – mpc T + I + G + NX + mpc Y Y – mpc Y = C – mpc T + I + G + NX (1 – mpc) Y = C – mpc T + I + G + NX – – – – –– – – – – –– – – – – – – – – – – – – –– –– –– C – mpc T + I + G + NX (1 – mpc) Y =
Short-Run Equilibrium Example – – – – – – –– –– – – 620 – 0.8 (250) + 220 + 300 +20 (1 – 0.8) C – mpc T + I + G + NX (1 – mpc) Y = Y = Y = 960 / 0.2 = 4,800
Chapter 23Appendix B The Multiplier in the Basic Keynesian Model
The Income and Expenditure Multiplier • Suppose autonomous spending decreases $10 and mpc is 0.8 • First decrease in spending is $10 • Leads to a decrease in output of $10 • Second decrease in spending is $8 • Third decrease is $6.40, etc. • Sum of the decreases in spending 10 + 8 + 6.4 + 5.12 + … = 10 [1 + 0.8 + (0.8)2 + (0.8)3…]
Income and Expenditure Multiplier • To find the sum of the series, we need a relationship when x is between 0 and 1 • In our case, x = 0.8 10 [1 + 0.8 + (0.8)2 + (0.8)3…] = 10 = 10 = 10 (1 / 0.2) = 10 (5) = 50 • In this case, the multiplier is 5 1(1 – x) 1 + x + x2 + x3 + x4 + … = = multiplier 1(1 – x) 1(1 – 0.8)