投資期末總復(fù)習(xí)市公開課獲獎(jiǎng)?wù)n件

1、投資、期末復(fù)習(xí)李法強(qiáng)第1頁第1頁課堂上關(guān)于動(dòng)態(tài)不一致性一點(diǎn)補(bǔ)充：表明通縮、通脹都厭惡長(zhǎng)期最優(yōu)為何是通脹為0？由于長(zhǎng)期通脹時(shí)u=u*第2頁第2頁投資：紅字為考點(diǎn)，其它為難點(diǎn)投資比GDP波動(dòng)大，是GDP波動(dòng)主要原因之一折舊包括物理折舊、經(jīng)濟(jì)折舊（過時(shí)），但是在計(jì)算合意資本存量時(shí)候那個(gè)depreciation應(yīng)當(dāng)看做是加上經(jīng)濟(jì)折舊投資理論即資本需求理論（資本需求超出資本供應(yīng)時(shí)產(chǎn)生投資），投資是流量，資本是存量。MPK=rc這是邊際收益等于邊際成本，rc為rental cost加速模型（離合意資本存量越遠(yuǎn)，投資越快）貌似會(huì)考PV辦法？老師課堂上開了個(gè)玩笑。要知道：預(yù)期收益率（風(fēng)險(xiǎn)溢價(jià)+無風(fēng)險(xiǎn)、平均回報(bào)

2、率）關(guān)于存貨投資（為何要存貨?應(yīng)對(duì)未來需求、平滑、少次大量訂單生產(chǎn)比較節(jié)約成本、不可避免）第3頁第3頁 合意資本存量Firms borrow to buy capitalborrow cost, i.e., interest rate, i.Price of capital changes, inflation rate, p.loss value in the capital, i.e., depreciation rate, d. Cobb-Douglas Example第4頁第4頁 考試應(yīng)當(dāng)是：給出數(shù)據(jù)求K* 再問當(dāng)rc或生產(chǎn)函數(shù)參數(shù)改變 時(shí)K*怎么改變KMPK, rcMPKrcK*De

3、sired capital stock第5頁第5頁KMRC, rcMPKrcK*rcMPK第6頁第6頁/10/107Flexible accelerator modelWhen the desired capital stock exceeds the existing capital stock, investment starts to fill the gap.The flexible accelerator model: the larger the gap the more rapid a firms rate of investment.第7頁第7頁/10/108Capital S

4、tock Adjustment第8頁第8頁課后Tech 66.a. From K* = (Y)/rc = K* = (0.3)(5)/(0.12) = 12.56.b. From K* = (0.3)(6)/(0.12) = 15 6.c. From I1 = (K* - Ko) = I1 = (0.4)(15 - 12.5) = (0.4)(2.5) = 1 = in the first year, net investment will be I1 = $1 trillion, so the new capital stock will be K1 = $13.5 trillion. Fr

5、om I2 = (K* - K1) = I2 = (0.4)(15 - 13.5) = 0.6 = in the second year, net investment will be I2 =$0.6 trillion and therefore the new capital stock will be K2 = $14.1 trillion. 6.d. As indicated above, the answers in 6.c. refer to net investment, that is, an addition to the capital stock. Gross inves

6、tment would include replacement of worn out capital.第9頁第9頁Outline失業(yè)和通脹政策實(shí)行效果動(dòng)態(tài)不一致性考試范圍：投資章節(jié)中最后一張ppt黃色部分去掉ch9第10頁第10頁老師上課統(tǒng)計(jì)（紅色為概念性）Ch10Is-LM模型，會(huì)畫圖分析，會(huì)數(shù)值計(jì)算Ch12算是比較難一章，畫圖要掌握，計(jì)算不要求新一些比較主要概念，比如說什么是匯率、什么是完美資本流動(dòng)、固定匯率、浮動(dòng)匯率、真實(shí)匯率需要背誦哦！Ch7失業(yè)率計(jì)算，請(qǐng)細(xì)心點(diǎn)！u=失業(yè)人口/勞動(dòng)力數(shù)量失業(yè)分類失業(yè)成本什么是自然失業(yè)率第11頁第11頁老師上課統(tǒng)計(jì)：Ch7通貨膨脹分類：可預(yù)期不可預(yù)期、

7、溫和惡性、成本推進(jìn)需求拉動(dòng)結(jié)構(gòu)型通脹。不同類型通脹成本不同Ch11重點(diǎn)章節(jié)貨幣政策、財(cái)政政策畫圖分析數(shù)值計(jì)算考評(píng)方式：給出一個(gè)政策，算出后果；給出一個(gè)政策目標(biāo)，設(shè)計(jì)出一個(gè)政策（或政策組合）特殊情形（流動(dòng)性陷阱、古典情形、不愿借貸）開放經(jīng)濟(jì)財(cái)政政策和貨幣政策（畫圖）政策影響還需要描述消費(fèi)、投資、進(jìn)出口怎樣改變第12頁第12頁Ch17重點(diǎn)時(shí)滯類別（內(nèi)部（認(rèn)識(shí)、決議、行動(dòng)）、外部）財(cái)政政策和貨幣政策時(shí)滯區(qū)分掌握不確定性環(huán)境下政策分析：對(duì)比不確定性情況下政策和確定性下政策影響不同規(guī)則行事、相機(jī)抉擇動(dòng)態(tài)不一致性詳細(xì)例子計(jì)算（就是類似于答疑課件那種題）Ch13生命周期理論最簡(jiǎn)樸形式：每一期消費(fèi)一樣多不同類

8、別收入邊際消費(fèi)傾向不同（需要知道怎么來計(jì)算其邊際消費(fèi)傾向）第13頁第13頁Ch14資本存量需求求法（合意資本存量求法，參考課后tech 6）投資加速模型（不會(huì)馬上填補(bǔ)缺口，缺口越大投資越大，有一個(gè)乘數(shù)拉姆達(dá)）提議：老師ppt看一下，homework過一遍若有時(shí)間，看書本，課后作業(yè)學(xué)霸世界老師不懂第14頁第14頁政策實(shí)行時(shí)滯類別（內(nèi)部（認(rèn)識(shí)、決議、行動(dòng)）、外部）財(cái)政政策和貨幣政策時(shí)滯區(qū)分掌握不確定性環(huán)境下政策分析：對(duì)比不確定性情況下政策和確定性下政策影響不同規(guī)則行事、相機(jī)抉擇動(dòng)態(tài)不一致性詳細(xì)例子計(jì)算（就是類似于答疑課件那種題）第15頁第15頁P(yáng)olicyMonetaryFiscalInside

9、lagRecognition -DecisionShortLongActionShortLongOutside lagLongShort這里意思是：M和F在結(jié)識(shí)時(shí)滯上沒有誰比較長(zhǎng)誰比較短比較注意：結(jié)識(shí)時(shí)滯無論對(duì)于貨幣或財(cái)政政策都是可正可負(fù)長(zhǎng)短都是相正確：應(yīng)當(dāng)解釋為M比F長(zhǎng)或M比F短，這樣才是比較合理若問：為何某某比某某長(zhǎng)？用傳導(dǎo)機(jī)制解釋！第16頁第16頁用下列機(jī)制來解釋時(shí)滯快慢擴(kuò)張性貨幣政策： iIY Md Md YIi擴(kuò)張性財(cái)政政策：GY Md iI Ii Md Y第17頁第17頁考題Suppose that GDP is $900,000 below its potential level

10、 this period, and will be $400,000 below its potential level next period, and then will return to the potential level. The multiplier for government purchases is 4.1.Assume that the effects of the increased government spending are immediate. What policy actions can be taken to keep GDP as close to t

11、he potential level as possible each period?2.Assume that there is a one-period outside lag for the effects of government spending. What policy actions can be taken to keep GDP as close to the potential level as possible each period?第18頁第18頁Answer:1.2. 注：以上政府購買增長(zhǎng)量是相對(duì)初始政府購買，而不是上一期政府購買第19頁第19頁Homework難

12、題 Suppose government purchase increases by $1 billion today, GDP will increases by $1 billion this period and $2 billion next period. The government wants to keep GDP always on potential level. (1) When GDP falls by $3 billion from potential level permanently, what would the government do? (2) What

13、is your suggestion for the government? 第20頁第20頁答案：1、自己算一下前幾期，并闡明后續(xù)會(huì)越來越大即可2、提議是始終保持1刺激第21頁第21頁. Uncertainty 不擬定性注意傳導(dǎo)機(jī)制解釋：不擬定什么時(shí)候會(huì)發(fā)生干擾，政府不擬定政策會(huì)對(duì)經(jīng)濟(jì)產(chǎn)生如何影響。這是由于：（反應(yīng)、干擾、結(jié)構(gòu)） 不知道公眾預(yù)期和反應(yīng) 預(yù)測(cè)干擾存在困難 不知道經(jīng)濟(jì)真實(shí)結(jié)構(gòu)（經(jīng)濟(jì)正確模型，給定模型參數(shù)值）第22頁第22頁. Uncertainty 不擬定性1. 反應(yīng)不擬定性假設(shè)政府決定暫時(shí)性減免稅收以刺激疲軟經(jīng)濟(jì) 暫時(shí)性減稅不會(huì)影響長(zhǎng)期收入，因此，MPC很小，需要更大減稅幅度

14、消費(fèi)者也許認(rèn)為減稅會(huì)比宣布連續(xù)時(shí)間長(zhǎng)，減稅部分MPC大，則小幅度減稅就足夠了2. 不擬定性與政策乘數(shù)不擬定性政策效果不擬定性采用政策組合分擔(dān)風(fēng)險(xiǎn)。第23頁第23頁. Uncertainty 不擬定性Homework 3 : Multiplier UncertaintyLucas批判：通常系數(shù)（和）依據(jù)歷史數(shù)據(jù)預(yù)計(jì)，并隱含假定其盼望含有時(shí)間不擬定性。貨幣等改變經(jīng)濟(jì)主體行為改變（對(duì)政策改變最優(yōu)反應(yīng)）系數(shù)改變假定系數(shù)不變政策效果分析也許有偏。貨幣政策財(cái)政政策第24頁第24頁不擬定性第25頁第25頁Answer：求解步驟：(1) 列出不同乘數(shù)下Loss Function(2) 依據(jù)各種乘數(shù)概率計(jì)算E(

15、L)(3) 一階求導(dǎo)最小化E(L)第26頁第26頁規(guī)則規(guī)則與權(quán)變（discretion)Taylor rule: r* 是實(shí)際利率，*是目的通貨膨脹率，和反應(yīng)了對(duì)通貨膨脹和充足就業(yè)關(guān)懷程度。政府進(jìn)行宏觀經(jīng)濟(jì)管理目的是充足就業(yè)和物價(jià)穩(wěn)定，事實(shí)上執(zhí)行往往是較低失業(yè)率和略高通貨膨脹率。 請(qǐng)問，這屬于相機(jī)抉擇還固定規(guī)則？規(guī)則第27頁第27頁 權(quán)變（也叫相機(jī)抉擇）造成動(dòng)態(tài)不一致性 2. 動(dòng)態(tài)不一致相機(jī)決議政策制定者會(huì)被誘惑而采用與長(zhǎng)期利益不一致短期行動(dòng)。假定對(duì)政策制定者而言，損失函數(shù)為：短期P.C曲線：政策制定者宣布0通脹政策，公眾通脹預(yù)期第28頁第28頁動(dòng)態(tài)不一致性相機(jī)決議政策制定者會(huì)被誘惑而采用與長(zhǎng)

16、期利益不一致短期行動(dòng)。u*u*(1) 宣布零通脹目的政策（長(zhǎng)期最優(yōu)）CBA（最后長(zhǎng)期穩(wěn)定預(yù)期）第29頁第29頁動(dòng)態(tài)不一致性理性預(yù)期在理性預(yù)期下，由得，第30頁第30頁適應(yīng)性預(yù)期：u*u*CBA想法1第一階段：點(diǎn)A第一階段：政府依據(jù)Loss函數(shù)調(diào)整進(jìn)行決議：AB第二階段：回到充足就業(yè)水平BC第31頁第31頁動(dòng)態(tài)不一致性適應(yīng)性預(yù)期第32頁第32頁第33頁第33頁2.第34頁第34頁2.uu*t=1t=2t=3t=第35頁第35頁動(dòng)態(tài)不一致性 第二題Suppose the short-run Phillips curve is given by ，where and for t1a. Suppose

17、 that the government wants to keep unemployment rate at 3%.What is the inflation rate at t = 3 ? Do you think the government should persist in keeping the unemployment rate at 3%? Why?09級(jí)期末考第六題第36頁第36頁 . Dynamic Inconsistency 動(dòng)態(tài)不一致性 b. Suppose the loss function for the government is ,where u * is th

18、e natural rate of unemployment. In each period the government chooses the value of unemployment rate to minimize the value ofloss function. What are the unemployment rate and inflation rate at t = 3 ?c. The loss function for the government is as in problem b. What combination of unemployment rate and inflation rate does the government prefer in the long run? Why?09級(jí)期末考第六題第37頁第37頁 . Dynamic Inconsistency 動(dòng)態(tài)不一致性 09級(jí)期末考第六題答案a. 第38頁第38頁 . Dynamic Inconsistency 動(dòng)態(tài)不一致性 09級(jí)期末考第六題答案b. 第39頁第39頁 . Dynamic Inconsis