AD I & AD II

Mankiw CH 11- CH 12AD I & AD IIMarita EitunaBuilding the IS-LM ModelAggregate Demand IPENDAHULUANGreat Depression pada tahun 1930-an fluktuasi ekonomi yang besar dan menyengsarakan

Keabsahan teori ekonomi klasik dipertanyakan karena tidak mampu menjelaskan depresi tersebut

Banyak ekonom percaya bahwa perlu ada model baru

Pada tahun 1936, John Maynard Keynes melakukan revolusi terhadap ilmu ekonomi melalui bukunya The General Theory of Employment, Interest, and Money

Keynes menyatakan bahwa permintaan yang rendah bertanggung jawab terhadap kemerosotan ekonom

Ia mengkritik teori klasik karena mengasumsikan bahwa hanya penawaran agregat-modal, tenaga kerja, dan teknologi- yang menentukan pendapatan nasional

Para ekonom dewasa ini menggabungkan kedua pandangan ini dengan model permintaan agregat dan penawaran agregat yang diperkenalkan pada bab 9slide 4The Big Picture :Teori Fluktuasi Jangka-PendekKeynesianCrossTheory of Liquidity PreferenceIScurveLM curveIS-LMmodelAgg. demandcurveAgg. supplycurveModel of Agg. Demand and Agg. SupplyExplanation of short-run fluctuations4Permintaan Agregat IPada bab ini kita meneruskan materi tentang fluktuasi ekonomi dengan model permintaan agregat yang merupakan interpretasi dari teori Keynes, yaitu model IS-LM

IS investment dan saving. Kurva IS menyatakan apa yang terjadi pada pasar barang dan jasa

LM liquidity dan Money. Kurva LM menyatakan apa yang terjadi pada pasar uangPASAR BARANG DANKURVA IS :Keynesian CrossPasar Barang dan Kurva ISKurva IS menyatakan hubungan antara tingkat bunga serta tingkat pendapatan yang muncul di pasar barang dan jasa

Keynesian Cross adalah model dasar untuk menjelaskan hubungan ini

Actual expenditure (Y): jumlah uang yang dikeluarkan rumah tangga, perusahaan, dan pemerintah atas barang dan jasa (real GDP)

Planned expenditure (E): jumlah uang yang akan dikeluarkan rumah tangga, perusahaan, dan pemerintah atas barang dan jasa

The Economy in Equilibrium Actual expenditure = Planned expenditure Y = Eslide 8Keynesian Crossincome, output, Y EplannedexpenditureY =E E =C +I +G AActual ExpenditurePlanned expenditureTitik A merupakan keseimbangan Keynesian Cross

Di titik A, actual expenditure sama dengan planned expenditure 8The equilibrium point is the value of income where the curves cross.

Be sure your students understand why the equilibrium income appears on the horizontal and vertical axes. Answer: In equilibrium, E (which is measured on the vertical) = Y (which is measured on the horizontal).

slide 9An increase in government purchases (G)Y EE =Y E =C +I +G1E1 = Y1 G Y

The government-purchases multiplier:

GLooks like Y>G

E =C +I +G2ABE2 = Y2Y

9Explain why the vertical distance of the shift in the E curve equals G: At any value of Y, an increase in G by the amount G causes an increase in E by the same amount.

At Y1, there is now an unplanned depletion of inventories, because people are buying more than firms are producing (E > Y).

slide 10An increase in taxesY EE =Y E =C1 +I +GE1 = Y1Tax Multiplier :

CTax C YE =C2+I +GABY

10Experiment: An increase in taxes (note: the book does a decrease in taxes)

Suppose taxes are increased by T. Because I and G are exogenous, they do not change. However, C depends on (YT). So, at the initial value of Y, a tax increase of T causes disposable income to fall by T, which causes consumption to fall by MPC T. Because consumption falls, the change in C is negative: C = MPC T

C is part of planned expenditure. The fall in C causes the E line to shift down by the size of the initial drop in C.

At the initial value of output, there is now unplanned inventory investment: Sales have fallen below output, so the unsold output adds to inventory.

In this situation, firms will reduce production, causing total output, income, and expenditure to fall.

The new equilibrium is at Y2, where planned expenditure once again equals actual expenditure/output, and unplanned inventory investment is again equal to zero. slide 11Y2Y1Y2Y1Deriving the IS curve r I Y Y ErY E =C +I (r1 )+G E =C +I (r2 )+G r1r2E =YIS I(r)I(r1)I(r2)r2r1Interest rate, rInvestment, II11slide 12Y2Y1Y2Y1

Kebijakan Fiskal dan Pergeseran Kurva IS : GPada tingkat r tertentu, G E YY ErY E =C +I (r1 )+G1 E =C +I (r1 )+G2 r1E =YIS1IS2Maka, IS bergeser ke kananG12PASAR UANG DAN KURVA LM :The Theory of Liquidity Preferenceslide 14Keseimbangan di Pasar UangThe Theory of Liquidity Preference : mengasumsikan bahwa keseimbangan suplai uang real adalah tetap

Tingkat bunga menyesuaikan untuk menyeimbangkanpermintaan dan penawaran uang:M/P real money balancesrinterestrate

L (r )

14slide 15Cara Bank Sentral Menaikan Tingkat BungaUntuk meningkatkan r, Bank sentral mengurangi MM/P real money balancesrinterestrate

L (r ) r1r2

Ketika M (turun) r (naik)Ketika M (naik) r (turun)15slide 16The LM curveNow lets put Y back into the money demand function:The LM curve is a graph of all combinations of r and Y that equate the supply and demand for real money balances.The equation for the LM curve is:

16slide 17Deriving the LM curveM/P r

L (r , Y1 ) r1rYY1r1LM(a)The market for real money balances(b) The LM curveL (r , Y2 ) r2r2Y217slide 18How M shifts the LM curveM/P r

L (r , Y1 ) r1r2rYY1r1r2LM1(a)The market for real money balances(b) The LM curveLM2

18If youre as anal as I am, you might consider helping your students understand the analytical difference between looking at a shift as a horizontal shift and looking at it as a vertical shift.

We can think of the LM curve shift as a vertical shift:When the Fed reduces M, the vertical distance of the shift tells us what happens to the equilibrium interest rate associated with a given value of income.

Or, we can think of the LM curve shifting horizontally:When the Fed reduces M, the horizontal distance of the shift tells us what would have to happen to income to restore money market equilibrium at the initial interest rate. (The graphical analysis would be a little different than whats depicted on this slide.)

MODEL IS-LMDengan model IS-LM, kita aplikasikan tiga kasus berikut :

1) Penyebab fluktuasi pendapatan nasional

2) How IS-LM fits into the model of aggregate supply and aggregate demand in Chapter 9

3) The Great DepressionrYLM(P0)ISr0Y0The IS-LM Model of ADPENGARUH KEBIJAKAN FISKAL TERHADAP KURVA IS DAN KESEIMBANGAN EKONOMI Perpotongan kurva IS dan kurva LM menentukan tingkat pendapatan nasional dan tingkat bunga pada tingkat harga tertentu.

Jika kurva IS atau LM bergeser, keseimbangan perekonomian jangka pendek berubah dan pendapatan nasional berfluktuasi.

Kita akan menganalisis bagaimana perubahan dalam kebijakan dan guncangan menyebabkan kurva IS dan LM bergeser. Explaining Economic Fluctuation with IS-LM Model LMrYISA+GKenaikan pengeluaran pemerintah akan menaikan tingkatPendapatan sebesar G/(1- MPC).ISBKurva IS bergeser ke kanan sebesar G/(1- MPC) yang akan menaikkan pendapatan dan tingkat bungaG IS ke kanan Y rLMrYISA-TPenurunan pajak akan menaikan tingkat pendapatan sebesarT MPC/(1- MPC).ISBKurva IS bergeser ke kanan sebesar T MPC/(1- MPC) yang akan menaikan pendapatan dan tingkat bungaT IS ke kanan Y rPENGARUH KEBIJAKAN MONETER TERHADAP KURVA IS DAN KESEIMBANGAN EKONOMI ISrYLMALM B+MJika money supply dinaikan, kurva LM akan bergeser ke kanan, tingkat bunga turun dan pendapatan naikM orang menggunakan kelebihan uang untuk ditabung atau membeli obligasi tingkat bunga (r) turun investasi yang direncanakan (I) naik pengeluaran yang direncanakan, produksi dan pendapatan naik keseimbangan berubah dari A ke BM LM ke kanan r Y Pada chapter sebelumnya, ditunjukkan bahwa dalam jangka pendek, ketika harga-harga kaku, kenaikan money supply akan menaikkan pendapatan, tp tidak menjelaskan bagaimana kebijakan moneter menaikan permintaan terhadap barang & jasa.

Model IS-LM menunjukkan pengaruh kebijakan moneter terhadap pendapatan dan tingkat bunga :

M r I permintaan terhadap barang & jasa Y

monetary transmission mechanism(Mekanisme transmisi kebijakan moneter)

Monetary Transmission MechanismMODEL IS-LM SEBAGAI TEORI ADslide 29Y1Menurunkan Kurva AD dari Kurva IS-LMY rY PISLM(M/P1)ADP1Y1r1P (M/P ) LM ke kiri r Y LM (M/P2 )r2P2Y2Y229It might be useful to explain to students the reason why we draw P1 before drawing the LM curve:The position of the LM curve depends on the value of M/P. M is an exogenous policy variable. So, if P is low (like P1 in the lower panel of the diagram), then M/P is relatively high, so the LM curve is over toward the right in the upper diagram. If P is high, like P2, then M/P is relatively low, so the LM curve is more toward the left. Because the value of P affects the position of the LM curve, we label the LM curves in the upper panel as LM(P1) and LM(P2).

slide 30Monetary policy and the AD curveY PISLM(M1/P1)AD1P1Y1Y1r1Bank sentral dapat menaikan AD dengan cara:

M LM ke kanan

Y r r Y P tetap AD bergeser ke kananLM(M2/P2)Y2Y2AD2r230Its worth taking a moment to explain why we are holding P fixed at P1:To find out whether the AD curve shifts to the left or right, we need to find out what happens to the value of Y associated with any given value of P. This is not to say that the equilibrium value of P will remain fixed after the policy change (though, in fact, we are assuming P is fixed in the short run). We just want to see what happens to the AD curve. Once we know how the AD curve shifts, we can then add the AS curves (short- or long-run) to find out what, if anything, happens to P (in the short- or long-run).

slide 31Y1Y1r1Fiscal policy and the AD curveY rY PIS1LMAD1P1Expansionary fiscal policy (G and/or T ) increases agg. demand:T IS ke kanan Y r

Y at each value of PIS2AD2Y2Y2r231INTERAKSI ANTARA KEBIJAKAN FISKAL DAN MONETER