宏觀經(jīng)濟學(xué)課件Cha

1、17-117-2chapter17policy item item item etc.mcgraw-hill/irwinmacroeconomics, 10e 2008 the mcgraw-hill companies, inc., all rights reserved.17-3introductionin this chapter we examine how policymakers formulate appropriate policy measuresmust consider:timinguncertaintyhow individuals will respond to sp

2、ecific policiesrole of credibilitymonetary or fiscal policy, or a mixdifferent policy instrumentsdifferent intermediate and ultimate targets17-4lags in the effects of policysuppose the economy is at full employment:affected by a negative aggregate demand disturbance reduces the equilibrium level of

3、income below full employmentno advance warning of disturbance no policy action taken in anticipation of its occurrencepolicymakers must decide:1.should they respond to the disturbance?2.if so, how should they respond?17-5lags in the effects of policyis the disturbance permanent (or persistent) or te

4、mporary?figure 17-1 illustrates a temporary aggregate demand shocka one period reduction in consumption best policy is to do nothing at alltodays policy actions take time to have an effect would hit economy after back at full-employment level, driving it away from the optimal levelinsert figure 17-1

5、 here17-6lags in the effects of policypolicymaking is a process:takes time to recognize and implement a policy actiontakes time for an action to work its way through the economyeach step involves delays or lags:1.inside lagsrecognition lagsdecision lagsaction lags2.outside lagsinside lags: the time

6、period it takes to undertake a policy actionrecognition lag: the period that elapses between the time a disturbance occurs and the time the policymakers recognize that action is requiredlag is negative if the disturbance is predicted and appropriate policy actions considered before it occurs (ex. in

7、crease money supply prior christmas)lag is typically positive17-7lags in the effects of policypolicymaking is a process:takes time to recognize and implement a policy actiontakes time for an action to work its way through the economyeach step involves delays or lags:1.inside lagsrecognition lagsdeci

8、sion lagsaction lags2.outside lagsinside lags: the time period it takes to undertake a policy actiondecision lag: the delay between the recognition of the need for action and the policy decisiondiffers between monetary and fiscal policyfomc meets regularly to discuss and decide on policy17-8lags in

9、the effects of policypolicymaking is a process:takes time to recognize and implement a policy actiontakes time for an action to work its way through the economyeach step involves delays or lags:1.inside lagsrecognition lagsdecision lagsaction lags2.outside lagsinside lags: the time period it takes t

10、o undertake a policy actionaction lag: the lag between the policy decision and its implementationalso differs for monetary and fiscal policymonetary policy makers typically act immediatelyfiscal policy actions are less rapid administration must prepare legislation and then get it approved17-9lags in

11、 the effects of policypolicymaking is a process:takes time to recognize and implement a policy actiontakes time for an action to work its way through the economyeach step involves delays or lags:1.inside lagsrecognition lagsdecision lagsaction lags2.outside lagsoutside lags: time it takes a policy m

12、easure to work its way through the economyinside lags are discrete, but outside lags are typically distributed lagsonce a policy action has been taken, its effects on the economy are spread out over timeimmediate impacts may be small, but other effects occur later17-10lags in the effects of policyfi

13、gure 17-2 illustrates the dynamic multipliershows the effects of a once-and-for-all 1 percent increase in the money supply in period zeroimpact is initially very small, but continues to increase over a long period of timewhy are there outside lags? monetary policy: initially impacts investment via i

14、nterest rates, not incomewhen ad ultimately affected, increase in spending itself produces a series of induced adjustments in output and spendinginsert figure 17-2 here17-11monetary versus fiscal policy lagsfiscal policy directly impacts aggregate demand affect income more rapidly than monetary poli

15、cy shorter outside lags than monetary policy longer inside lags than monetary policylong inside lags makes fiscal policy less useful for stabilization and used less frequently to stabilize the economyit takes time to set the policies in action, and then the policies themselves take time to affect th

16、e economy. further difficulties arise because policymakers cannot be certain about the size and the timing of the effects of policy actions.17-12expectations and reactionsgovernment uncertainties about the effects of policies on the economy arise because:1.policymakers do not know what expectations

17、firms and consumers have2.government does not know the true model of the economywork with econometric models of the economy in estimating the effects of policy changesan econometric model is a statistical description of the economy, or some part of it17-13reaction uncertaintiessuppose the government

18、 decides to cut taxes to stimulate a weak economy temporary tax cuthow big of a cut is needed?one possibility: temporary tax cut will not affect long-term income, and thus not long-term spending large tax cut neededalternatively: consumers may believe tax cut will last longer than announced, and mpc

19、 out of tax cut is larger smaller tax cut might be sufficientif the government is wrong about consumers reactions, it could destabilize rather than stabilize the economy.17-14uncertainty and economic policypolicymakers can go wrong in using active stabilization policy due to:uncertainty about the ex

20、pectations of firms and consumersdifficulties in forecasting disturbanceslack of knowledge about the true structure of the economyuncertainty about the correct model of the economyuncertainty about the precise values of the parameters within a given model of the economyinstead of choosing between fi

21、scal and monetary policies when themultipliers are unknown, best to employ a portfolio of policy instruments. diversification17-15targets, instruments, and indicatorseconomic variables play a variety of roles in policy discussionsuseful to divide them into targets, instruments, and indicatorstargets

22、: identified goals of policyultimate targetsex. “to achieve zero inflation”intermediate targetsex. targeting money growthused to achieve ultimate target17-16targets, instruments, and indicatorseconomic variables play a variety of roles in policy discussionsuseful to divide them into targets, instrum

23、ents, and indicatorsinstruments: tools policymakers manipulate directlyex. an exchange rate targetindicators: economic variables that signal us as to whether we are getting closer to our desired targetsex. increases in interest rates (indicator) sometimes signal that the market anticipates increased future inflation (target)provide useful feedback policymakers can use to adjust the instruments in order to do a better job of hitting targets17-17rules versus discretion in determining how po