宏观经济学经济波动理论的进展

经济学原理（宏观部分）经济学原理是指在经济学范围内，对人类的各种经济现象和经济政策进行系统分析、阐述经济规律、解释经济现象的一般性原则和基本理论。

宏观经济学是指对整个经济体制和经济活动的总体分析、研究和预测。

以下将从宏观经济学的角度出发阐述如下原理：一、经济增长原理经济增长是指经济总量在一段时间内持续增加的过程。

在宏观经济学中，经济增长是评价一个国家或地区经济发展水平的重要指标。

经济增长的原理主要体现在两个方面：劳动生产率增长和资本积累。

劳动生产率提高是指单位劳动力所创造的产品数量增加，主要通过科技进步和技术创新来实现。

资本积累是指企业和个人通过储蓄和投资来增加生产资本的数量，从而增加生产规模和产出量。

劳动生产率提高和资本积累是经济增长的双轮驱动力。

二、货币原理货币是现代经济中不可或缺的一部分。

货币在宏观经济中的作用主要是作为交易媒介、计算单位和价值储存器。

货币在经济中的发挥效用是在于货币的增长速度要和商品和服务的生产相匹配，因为货币的增长速度过快会导致通货膨胀，货币的增长速度过慢则会导致经济增长的乏力。

货币供应量的调整控制以及货币供应量的稳定，是实现经济稳定增长的重要经济原则。

三、失业原理经济稳定增长不仅涉及到经济总量的增长和生产力的提高，还需要解决人民就业的问题。

失业原理是针对宏观经济中劳动力的失业现象的解释。

它分为结构性失业和摩擦性失业。

结构性失业对应的是经济结构变化的改变，原职业岗位的消失、替代或改变，而没有相应的新的工种可以提供让失业的劳动力重新就业的机会；摩擦性失业则是就业空缺和求职工人之间信息沟通的问题，导致就业岗位需要的人员和找到工作的人员的时间、地域等方面上的错配。

减轻失业需要政府有针对性推出减税、扩大公共支出以及资本市场政策等多种措施。

四、通货膨胀原理通货膨胀是指物价水平在一段时间内持续上涨的过程。

通货膨胀来源主要是货币过量发行而货币需求不足引起的通货膨胀和供需失衡引起的通货膨胀。

罗伯特㊃霍尔对宏观经济学的贡献∗肖小龙内容提要:罗伯特㊃霍尔是美国著名的宏观经济学家,他在消费理论㊁货币理论和经济周期波动理论等方面做出了突出贡献㊂霍尔的随机游走假说使消费理论研究进入到一个新的发展阶段;他提出的新货币经济学被认为是最激动人心地重新审视了传统货币理论的研究;他在经济周期波动理论中的研究,视角新颖地阐释了劳动力市场对经济周期波动的传导机制㊂关键词:罗伯特㊃霍尔㊀随机游走假说㊀新货币经济学㊀经济周期波动理论㊀㊀罗伯特㊃霍尔(R o b e r tE .H a l l)是美国著名的经济学家㊂1943年出生于美国加州,1967年获麻省理工学院经济学博士学位,1967-1978年间先后执教于加州大学伯克利分校和麻省理工学院㊂1978年以后任斯坦福大学经济学系教授及该校胡佛研究所高级研究员至今㊂霍尔在美国经济学界一直非常活跃,拥有众多的学术头衔㊂自1977起担任国家经济研究局(N B E R )经济波动与经济增长的研究项目主任,并兼任该局下属经济周期测定委员会主席㊂2004年当选为美国国家科学院(N A S )院士,2010年担任美国经济学联合会会长,同时,他还是美国艺术与科学院院士㊁计量经济学会会士㊂此外,霍尔还一直致力于为美国司法部㊁财政部和联邦储备委员会等许多政府机构提供国家经济政策方面的咨询工作㊂与持有理性预期思想的经济学家对凯恩斯理论的排斥态度不同,霍尔主张吸收传统经济理论的合理成分㊂他肯定了需求对生产的决定性作用,据此对宏观经济运行中发生的现象进行考察,并将这些现象引入其经济学理论㊂同时,他也肯定了政府调节需求的经济政策对经济波动的缓和作用㊂这一思路在霍尔的早期研究中就有所体现,比如他与普林斯顿大学教授阿尔文㊃拉布什卡(A l v i nR a b u s h k a )在合著的‘低税㊁简税㊁单一税“(1983)和‘单一税“(1985)中,提出了以减低税率㊁扩展税基㊁简化税制为特征的单一税设想(t h e f l a t t a x ),试图通过对国家税收政策的改革,调整利率以刺激投资需求㊁消费需求,在不扭曲市场过程的前提下,使经济运行保持自由竞争㊂单一税的提出,使霍尔获得了经济学界的广泛关注㊂在他看来,现有宏观经济理论研究依然缺乏合理的微观基础,在此后的研究中他试图利用理性预期和价格调整的观点,在粘性价格理论的基础上构建宏观经济学理论㊂霍尔的研究领域广泛,本文主要评述他在消费理论㊁货币理论和经济周期波动理论三个方面的突出贡献:(1)随机游走假说(R a n d o m W a l k i n g H y-po t h e s i s )相较于传统消费理论几乎是颠覆性的,极大地推动了消费理论研究进入一个新的发展阶段㊂(2)新货币经济学(N e w M o n e t a r y Ec o n o m i c s )思想被认为是最激动人心地重新审视传统货币理论的研究㊂(3)对于劳动力市场工资决定及在职搜索的一系列研究成果,成为了推动经济周期波动理论向前发展的重要力量㊂一㊁随机游走假说在现代宏观经济学中,消费的研究始于凯恩斯对于消费行为及其影响因素的解释,即收入与消费之间存在着某种稳定的函数关系㊂这一理论是基于消费者行为的假设基础之上,强调当期收入的绝对水平对于当期消费水平的重要作用,因此也被称之为绝对收入假说㊂然而,库兹涅茨(K u z n e t s ,1946)的研究显示了长期内的平均消费倾向基本保持不011 ∗肖小龙,西北大学经济管理学院,邮政编码:710127,电子邮箱:r o y_x x l @163.c o m ㊂基金项目:本文为教育部人文社科一般项目(11X J C 630010);陕西省社科基金项目(11E 028)资助成果㊂感谢匿名审稿人的意见,当然文中错误由作者负责㊂变㊂为此,经济学家开始将预期收入引入消费函数进行解释,其中,莫迪利亚尼(M o d i g l i a n i,1954)等的生命周期假说(L i f eC y c l e H y p o t h e s i s,L C H)和弗里德曼(F r i e d m a n,1957)的持久收入假说(P e r-m a n e n t I n c o m eH y p o t h e s i s,P I H)是两个经典的消费模型㊂前者说明了消费取决于收入,理性的消费者将根据效用最大化的原则使用一生的全部收入,安排其间的消费与储蓄,使一生中的收入等于消费㊂后者则认为,消费者会根据收入的稳定性来安排其消费与储蓄㊂在生命周期和持久收入假说的消费函数中,都将长期收入刻画为一个确定性的㊁可预期的因素,从而影响人们的消费㊂但现实的经验事实却是:未来收入是具有风险性和不确定性的㊂由此,许多学者将注意力转向不确定性条件下的预期收入对于消费函数的分析㊂霍尔是最早对此进行研究的学者之一㊂霍尔对消费理论的最大贡献在于他将理性预期引入到消费函数的分析中,在融合生命周期假说和持久收入假说的基础之上,发展成为随机游走假说㊂他认为按照生命周期/持久收入假说(L C/P I H),消费者对他们的长期消费能力形成估计,然后根据估计确定当前的消费㊂莫迪利亚尼在进行估计时采用了以不变价格计算的财富形式;弗里德曼则利用过去预期与过去实际间的差距来矫正对未来的预期,这样就造成了对估计函数的曲解㊂在‘随机影响生命周期-永久收入假说:理论和证据“(1978)一文中,霍尔构建了不确定条件下的跨期最优化消费模型,假设消费者可以对任何外部不确定性因素做出充分反应,那么消费者最大化期望效用的表达式可以写为:E tðs11+δæèöøs U c t+s(),其约束条件为:ðs11+ræèöøs c t+s-w t+s()=A t㊂则可以得到消费者在既定利率条件下的跨期最优条件,即欧拉方程(E u l e rE q u a t i o n),其表达式可以写为:uᶄ(c t+1)= [(1+δ)/(1+r)]uᶄ(c t)+εt㊂其中,c t是第t期的消费,εt是不可预期的随机变量㊂通过霍尔的推论,这一表达式可以简化为c t+1=λc t+εt㊂消费者可根据当期消费水平c t预测下一期的消费水平㊂由于现期可获得的关于未来收入的信息已经包含在现期持久收入中,这意味着在t期除了消费水平c t以外,没有可用的信息帮助预测未来消费,未来收入的不确定性对现期消费没有影响㊂霍尔的跨期最优消费模型考察了一个遵循理性预期的消费者,其潜在行为使消费轨迹表现为一个随机游走过程㊂也因为如此,随机游走假说表明了政策对消费的影响与其对持久收入的影响差不多㊂在假定持久收入不变条件下的政策分析中,消费也许被当作外生的㊂只有关于税收和其他政策工具的 新信息 (n e wi n f o r m a-t i o n)可以影响持久收入㊂霍尔在随机游走模型中将收入因素排除在消费函数的做法具有开创性意义,在20世纪80年代产生了巨大的影响㊂霍尔模型的结果与实际消费现象的抵触,使得许多文献基于这一框架展开计量检验,结果都拒绝随机游走假说㊂F l a v i n(1981)的研究显示消费变动与消费者的可预期收入变动是高度相关的,即存在消费的过度敏感性(e x c e s ss e n s i t i v i t y)㊂霍尔等在‘基于家庭面板数据的消费与暂时收入敏感性估计“(H a l l&M i s h k i n,1982)一文中,利用1969-1975年间美国两千户家庭的截面数据进一步对假说进行检验和分析,发现过度敏感性的问题确实存在㊂根据假说的扩展模型,样本中大约有80%的家庭服从了生命周期/持久收入假说,其余家庭的消费则对暂时性收入的反应要远远比对持久收入变动的反应强烈㊂同时,当期消费的变动与收入滞后项的变动存在强烈的负相关㊂事实上,由于信贷市场存在着信息不对称㊁不完全等问题,导致消费者在预期未来收入提高时,无法通过金融机构或非金融机构将自己的未来收入抵押进行自由借贷,只能用手中现有的收入进行消费㊂他们的结论显示,有约1/5比例的美国家庭受到流动性约束(l i q u i d i t y c o n s t r a i n t),从而无法进行自由借贷㊂在跨期消费选择条件下的最优消费路径研究中,对替代效应的估计是分析消费者跨期选择行为的一个重要内容㊂在‘消费的跨期替代性“(1988)一文中,霍尔的一个重要理论创新是利用食品的消费支出与利率变动构建了一个单一消费品模型,在此基础上讨论了不确定实际利率下的消费理论以及预期实际利率的测量方法,从理论上分析了利率对消费者跨期替代行为的影响,计量结果发现美国居民的跨期替代弹性接近于0,并且预期的实际利率变化对消费不足以产生实际影响㊂二、新货币经济学在20世纪80年代之前,传统的货币理论都建立在瓦尔拉斯一般均衡分析之上,直至哈恩(H a h n, 1965)提出了如果货币不具有正的价值,是否还能保证货币模型存在一般均衡的问题㊂后来的经济学家111‘经济学动态“2013年第11期们针对货币是否具有正价值给出了多种解释,诸如内含货币的效用函数(S i d r a u s k i,1967)以及货币先行模型(C l o w e r,1967)等㊂与这些解释不同,霍尔在费雪(F i s h e r,1913)提出的 补偿美元计划 (c o m-p e n s a t e dd o l l a r)方案基础上,汲取了布莱克(B l a c k, 1970)和法玛(F a m a,1980)的研究中抛弃以货币存在为前提的思想,试图找到一个尝试分离货币价值标准和流通媒介职能,从而稳定价格水平的方法㊂他指出金本位对于货币过量发行依然有限制作用,但传统的金本位与商品本位不同,即使选择一个最佳的商品本位,也应需要定期进行重新定义(H a l l, 1982)㊂在‘美国和英国的货币趋势:一个新货币经济学视角回顾“(1982)一文中,首次正式将这种探讨分离货币的流通手段和价值尺度职能,在自由放任的完全竞争市场条件下构建一个新支付体系的货币理论称之为 新货币经济学 ㊂与停留在思想性上的理论探索不同,霍尔还试图使竞争性支付体系实践化㊂他在讨论记账媒介时,建议一种由标准局(B u r e a uo f S t a n d a r d s)严格界定规格的资源单位作为记账单位,具体做法可以是被限制流通媒介作用的一定量硝酸铵(价值为33美分)㊁铜(价值为18美分)㊁铝(价值为36美分)和胶合板(价值为19美分)四种商品的组合(这些商品的价值以1967年的价格计算),命名为A N C A P (H a l l,1982)㊂并在其经典论文‘最佳信用货币体系“(1983)中系统阐述了建立一个现代信用货币体系的构想㊂他指出一个稳定的信用货币体系是整个社会努力的结果,事实上,作为具有特权的参与者,政府对于货币需求的变化会导致现行货币体系的不稳定,因此,在完全竞争条件下应该取消政府发行通货的特权,用调整向货币支付收益的规则来替代,以便稳定政府的货币需求,稳定物价水平㊂首先,霍尔明确了作为理想的货币信用体系应具备两个基本标准:在微观层面上,消除交易带来的无谓损失;在宏观层面上,保持一般价格水平的稳定并使实际产出接近均衡水平㊂其次,他建议选择 储备证书 (r e s e r v ec e r t i f i c a t e)作为货币工具㊂通过监管,强制或诱导公众持有储备证书;或以有吸引力的收益使公众自愿持有㊂当然,这种储备规则本身具有创造需求的可能,在低效的监管干预情况下,对储备证书的需求具有不稳定性,并且无法估计㊂霍尔认为可以让储备证书的需求对价格水平具有高弹性,微小的价格水平变化便足以抵消大幅度储备证书的需求变化㊂同时,他认为储备证书在货币体系中的关键功能是作为价值标准㊂一旦储备证书的购买力与价格水平紧密联系,银行也可以发行货币,政府没有必要对金融机构进行干预㊂霍尔构建了一个完全灵活价格的均衡经济模型,模型中描述了储备证书的利率如何通过对价格水平变动高度敏感的调整以达到均衡状态,价格水平高于目标值时,更高的收益率(相对于其他可选资产而言)可以提高需求,从而抑制了价格水平,反之同理㊂价格水平稳定于目标值,则储备证书的利率与其他资产收益率相等,这样就可以实现货币体系的微观目标和宏观目标㊂在霍尔货币信用体系下,其金融改革思想也是非常具有远见的㊂他提出向所有货币性负债的持有者支付利息(政府或许还有其他的债务在公众手中,这些债务用于各类交易但没有利息,比如货币)㊂再者,霍尔建议货币债券的利息率应与短期国库券的利率相一致,通过债务使经济在实体方面得到近乎充分的满足㊂其后,值得注意的是,他最富有洞察力的思想是建议货币债券与短期国库券的利息差异应该作为稳定价格平均水平的指数㊂当价格水平过低时,通过加大利息差来降低对货币债券的需求;而当价格水平过高时,通过降低利息差来提升对货币债券的需求㊂由于事先知晓利息差与价格水平相关联的规则,这种指标体系自动抵消了货币债券需求中的变化,并且能够稳定价格水平㊂事实上,霍尔建议包括在过去债券平均持有量的基础上,通过关注债券持有者,将利息差与未来价格水平的平均值挂钩㊂这项方案可以用于稳定未来预期价格的平均水平㊂由于通过资本收益支付的利息包含一般价格水平的变化,这部分利息有可能属于不良资金㊂对此,霍尔提出应当通过分红的形式支付利息㊂而且除了分红之外,价格水平有可能出现间断性的下跌,红利势必将会不断累积㊂可是,红利的实际支付可以在任一固定的时间间隔㊂霍尔提出了两种支付利息的方法:(1)政府的货币债券应当由诸如在美联储的账户构成,红利应当存入账户㊂(2)债券应当设置为大面额,并且政府应定期将账单邮寄给债券的持有者㊂最后,霍尔在金融改革的提议中还讨论了消除无效的货币规则,这些规则通常能够保证对政府金融债券的积极需求㊂金融机构的强制性储蓄要求将被利息的诱导所取代㊂霍尔也建议取消禁止持有私人小额有价证券,使私人货币得以存在㊂霍尔(1997,2002)的贡献还体现在他建立了一个在货币职能分离情况下控制价格水平的一般分析框架㊂他将价值单位定义为:价值单位是x t单位的211资源y ,设r t 为每单位资源相对于生活必需品成本的价值,则价值单位的购买力为z t =x t r t ,且价格水平为:P t =1z t =1x t r x ㊂这个定义没有说明货币单位资源含量x t 的变化能否引起资源购买力r t 或者货币的单位购买力z t 的变化,并且没有说明资源市场的干预如何影响r t 或其他经济变量㊂特别是等式没有表明货币的非中性㊂因此,霍尔指出,在该等式下控制价格水平的手段可以从三个方面展开讨论:(1)被动的价格水平控制㊂在没有政府干预的情况下让市场来决定r t ,并且让x t 保持一个不变的水平㊂在金本位制下,黄金价格流动机制控制价格水平㊂政府除了发行了少量足值金币以外,没有发行任何事务型债券,也不干预黄金市场㊂私人债券(包括银行券)面额都以美元来表示,它意味着,1美元的债务最终可以转换成0.04838盎司黄金㊂当黄金参与货币体系时,它本身是黄金需求和购买力的主导因素㊂由于黄金的货币角色,对它的需求也会随时改变,比如在金融恐慌的时候它的需求将上涨,这时公众寻求将以黄金来衡量的金融工具兑换为黄金本身㊂因此,在金本位制没能发挥作为黄金购买力行为的指导作用时,关注黄金的购买力不合适㊂(2)基于改变货币单位资源含量的价格水平控制㊂在没有政府干预下让市场来决定r t ,政府仅改变x t 以使价格水平接近常数㊂费雪补偿美元计划 (1913)的基本观点是规定足值的美元来购买生活必需品㊂如要将价格水平稳定在p 0,则规则为:x t =1p 0r t ㊂据此,费雪为价格稳定机制制定了详细的规则,其步骤为:首先,按制造商根据最新的货币单位定义而提出的价格衡量生活成本㊂其次,用测量的价格水平与目标价格p 0之间差额相同的比率来调整货币单位的资源含量x t ㊂费雪将黄金的使用假定为资源,所以他制定的规则在于,调整所需美元的黄金含量以保持美元的购买力为恒量㊂霍尔认为,黄金购买力的不稳定性,使其并不适合发挥基础资源的作用㊂比如当黄金价格和其他商品价格急剧上涨时,黄金购买力波动的根源是将防止由未来通货膨胀预期所带来的金融恐慌㊂这时公众对银行机构失去信心并有意以黄金和其他商品形式持有财富㊂他将费雪计划纳入一般分析框架,认为定义一个自稳定货币单位最可行的方法是使用一种具有更加稳定购买力的资源㊂理论上最好的方法是直接以购买生活必需品的成本的形式来定义价值单位,但前提是,这个定义下的资源必须是实际可以交易的㊂智利的 发展单位 (U F )的经验表明,将货币单位定义为x t 单位的标准证券是形成自稳定货币单位的成功实践㊂(3)基于干预资源市场的价格水平控制㊂使x t 保持为1,干预资源市场以稳定资源的购买力r t ,资源是政府发行的债券,政府通过干预来改变债券的供给㊂对资源市场的干预可以采用改变资源供给或改变资源收益的形式㊂第一种形式是控制资源供给㊂当资源是物质(比如黄金)时,政府可以通过改变公众掌握的资源的供给量来改变其购买力㊂但为了稳定资源的市场购买力,政府需要大量持有该资源,这使得这类物质作为资源的成本过高㊂因此,将金融债券作为资源(通过改变供应量来稳定价格水平)形成了所有现代经济体的货币体系基础㊂有价证券和货币都是无息储备,由于政府总是准备着以固定利率兑换不同储备,多样的有价证券形成希克斯复合商品(H i c k s i a nc o m p o s i t e g o o d ),霍尔建议将该复合品作为储备㊂单位储备的购买力由传统经济学的报酬(c o n s i d e r a t i o n s )标准决定㊂储备需求产生于其在实行交易过程中的有效性㊂若有储备要求则需求也更大,但是即使没有储备要求时需求也是正的㊂这样,问题可以表述为:在给定一定数量的1美元纸币(在实行交易时有用)的经济中,与一般的商品和服务相关的这些纸币的一般价值是什么?分析决定了变量r t 的水平㊂每个国家(除使用U F 的国家)都将货币单位的资源含量x t 定义为1,则价格水平可简化为单位储备购买力的倒数:p t =1r t ㊂在这个体系下,通过储备供给的调节实现对价格水平的控制,对储备的需求随着时间变化而波动㊂价格稳定要求供给的调整匹配需求的变动㊂此外,随着支付体系的运作有一个重要的低频随机因素㊂由于需求的不稳定性,价格稳定政策不是要规定储备的供给,而是通过这种反馈机制对需求的变动做出自动反应㊂第二种形式是控制资源收益㊂随着价格稳定的实现,政府要做的是控制价格水平㊂中央银行将使用储备数量作为控制价格水平的工具,这不可避免地导致大量无息贷款形式的储备交易,反之亦然㊂准备金需求与周㊁季节㊁气候相关的波动需要中央银行不断地买卖政府债券(通常以购回协议形式)㊂储备利率作为货币政策的日调节工具,代替了公开市场操作㊂在短期,中央银行调整储备利率311 ‘经济学动态“2013年第11期来盯住短期市场利率㊂中期,中央银行根据目标的通货膨胀来调整短期利率的目标值㊂通过调节短期利率自发稳定价格水平㊂如果p(t)为价格水平,n (t)为国库券的短期利率㊂储备利率的b(t)自动调节公式是bt()=nt()+p t()-1[]nt()-p(t㊃)㊂价格水平的目标值是1,如果价格水平上升至1以上,则储备利率上升,经济收缩㊂另外,公式表明通过降低储备利率和扩大通货膨胀数量可以实现实际通胀的调节㊂最后,霍尔还讨论了转变为电子货币后的价格水平控制㊂他指出,即使私人支付和电子支付的方法取代了中央银行的支付义务,为储备支付利息仍是控制价格水平的合适方法㊂在短期国库券市场上准备金率和市场利率的差别将会减小,以补偿由支票账户需求导致的准备金需求的减少㊂最终,当最后的支票账户和最后的美元钞票停止使用,准备金将被重视,这几乎完全是由于它的利息收益㊂毋庸置疑,霍尔是新货币经济学的开创者之一㊂他的货币理论不仅探索了分离货币职能从而实现货币理论与价值理论相统一的研究路径,更使这种思想上的探索具有现实的可操作性㊂他的新货币经济学在提出之时,并不为传统货币理论学者所接受㊂他们坚持帕廷金(1965)提出的传统观点,即货币系统不具有自动的资源配置功能,政府须对名义货币量和回报率进行强制性规定㊂约翰逊(J o h n s o n, 1986)指出,自由竞争支付体系将引起银行货币无节制的扩张行为,最终导致物价水平的失控㊂但随着电子货币的快速发展㊁金融创新日益在现实生活中体现活力,技术的不断进步使得交易与记账效率的改进成为可能,霍尔的自由竞争支付系统离现实越来越近,当代经济学家才逐渐意识到霍尔研究的前瞻性㊂鉴于对新货币经济学的巨大贡献,霍尔在学术界获得了较高的声望㊂格林菲尔德和耶格尔(G r e e n f i e l d&Y e a g e r,1983)在他们的经典论文‘稳定货币的自由竞争理论“中将布莱克㊁法玛㊁霍尔的研究成果命名为 B F H 体系㊂三、经济周期波动理论经济周期的波动问题一直是困扰宏观经济学的难题㊂以基德兰德和普雷斯科特(K y d l a n d&P r e-s c o t t,1982)为代表的经济学家对于实际经济周期理论(R e a lB u s i n e s sC y c l eT h e o r y,R B C)阐述中所运用的动态一般均衡模型,成为了解释经济周期波动问题的标准模型㊂标准的实际经济周期理论认为,经济周期的主要驱动因素来自于技术冲击,技术冲击与劳动生产率存在正向关系,市场中的经济主体具有理性预期,会根据工资㊁利率等经济变量产生的相对价格变化,在消费和劳动供给上做出相应的调整,由此,就业变化产生波动引致宏观经济波动㊂这也构成了研究经济周期波动的基本框架,即对冲击因素的辨识以及传导机制的解释㊂随着研究的深入,越来越多的学者发现,根据标准实际经济周期模型所做出的研究会带来一些无法信服的推论,例如将经济衰退与全要素生产率下降相联系,就意味着不得不承认技术退步的存在,这显然与现实情况并不符合㊂霍尔在‘美国工业中价格与边际成本的关系“(1988)一文中,他分析了在检验索洛残差的短期变化时,将一个对产出和雇佣劳动力很重要的外在决定因素即非技术冲击因素引入索洛等式中,当这个据有说服力的外因变量被发现与索洛余值有关系,它就反驳了竞争和固定收益的联合假说㊂他将军事开销的变化设定为外因变量,并且通过了检验㊂霍尔对经济周期波动理论发展的贡献主要体现在他对经济周期传导机制的解释上㊂霍尔关于劳动力市场对经济周期波动的分析,是建立在戴蒙德(P.D i a m o n d)㊁莫滕森(D.M o r t e n s e n)和皮萨里德斯(C.P i s s a r i d e s)基于搜寻匹配模型上的创新㊂其基本思想是劳动力的过度波动并非来自于劳动力的离职行为变化,反而是求职变量变化更显著地带来了波动,霍尔在‘就业波动与均衡的工资粘性“(2005)一文中展示了这一观点㊂他对美国2000年12月(经济繁荣期)与2002年12月(经济萧条期)企业招聘和岗位设定的相关数据进行比对:空职率分别为2.8%㊁1.8%;失业率分别为3.6%㊁5.7%;失业者就业率(j o b-f i n d i n g r a t e)分别为0.773㊁0. 338;空职失业率(v a c a n c y/u n e m p l o y m e n t r a t i o)分别为0.767㊁0.312㊂在经济繁荣时期,失业率非常低,此时空缺职位较多,企业雇佣态度积极,为招募投入大量资源导致失业者就业率高;相反在经济衰退时期,失业率非常高而空缺职位较少㊁企业没有雇佣意愿致使失业者就业率低㊂在经济扩张向经济衰退的过渡过程中失业率会大幅上升,而随后失业率的下降却是缓慢的㊂由于现代劳动力市场中社会力量的约束(比如抗削减工资等),工资具有粘性,较小的外生冲击放大了就业波动㊂411。

Name: __________________________ Date: _____________1. When a government spends more than it collects in taxes, it runs a:A) trade deficit.B) trade surplus.C) budget surplus.D) budget deficit.2. Government debt equals the:A) difference between current government purchases and taxes.B) difference between saving and investment.C) sum of past budget deficits and surpluses.D) M1 money supply.3. The amount by which government spending exceeds government revenues is called the______, and the accumulation of past government borrowing is called the ______.A) deficit; debtB) debt; deficitC) devaluation; deflationD) deflation; devaluation4. The government budget deficit is the ______, and government debt is the ______.A) amount by which imports exceed exports; amount by which government spendingexceeds government revenueB) amount by which government spending exceeds government revenue; amount bywhich imports exceed exportsC) amount by which government spending exceeds government revenue;accumulation of past government borrowingD) accumulation of past government borrowing; amount by which governmentspending exceeds government revenue5. If the debt of the U.S. federal government in 2008 was divided equally among thepeople in the United States, then the debt per person would equal approximately:A) $3,500.B) $35,000.C) $53,000.D) $153,000.6. Compared to the size of government debt as a percentage of GDP in other majorindustrial countries, the federal government of the United States:A) is one of the most heavily indebted governments.B) has accumulated a relatively small debt.C) has accumulated somewhat greater than average debt.D) is one of the least indebted governments.7. Historically, the primary cause of increases in government debt is:A) printing too much money.B) cutting taxes.C) increasing interest rates.D) financing wars.8. The large increase in U.S. government debt between 1980 and 1995 was unusualbecause it occurred:A) during peacetime.B) during an extended recessionary period.C) without increased government spending.D) without tax cuts.9. Relative to the size of GDP, the U.S. federal government debt was at its maximum:A) at the end of the Revolutionary War.B) at the end of the Civil War.C) at the end of World War II.D) following the 9/11 terrorist attacks in 2001.10. Holding other factors constant, the ratio of government debt to GDP can decrease as aresult of any of the following changes except:A) decreases in government spending.B) increases in GDP.C) decreases in tax revenues.D) decreases in transfer payments.11. If government debt is not changing, then:A) the economy is at long-run equilibrium.B) the government's budget must be balanced.C) GDP must equal the natural rate of output.D) capital per worker is constant.12. The factors most responsible for forecasts of the U.S. government debt spiraling out ofcontrol in the next half century are the projected:A) slowdowns in the rates of technological change and human capital growth.B) decrease in high-skilled domestic workers and the increase in immigration oflow-skilled workers into the United States.C) aging of the U.S. population and rising health care costs.D) increase in international competition and the outsourcing of U.S. jobs.13. An increase in the elderly population of a country affects fiscal policy most directlybecause:A) the elderly generally are not required to pay taxes.B) governments provide pensions and health care for the elderly.C) the elderly favor high interest rates on their savings.D) governments spend more on education as the proportion of the elderly increases.14. Which of the following is the most likely explanation of the August 2011 decision byStandard and Poor's to reduce its credit rating on U.S. government bonds?A) A U.S. government debt default was not a likely outcome, but was a possibility tooccur in the short term.B) The U.S. government budget deficit was too large.C) Strategies to reduce predicted U.S. government future budget deficits did notappear likely, making default a possibility.D) Foreign governments were no longer willing to lend to the U.S. government.15. In a time of inflation when the government budget is balanced in the conventional sense,the real (i.e., deflated) value of the government debt is:A) growing at the rate of inflation.B) growing, but at a rate less than the rate of inflation.C) constant.D) decreasing at the rate of inflation.16. In a time of inflation when the real (i.e., deflated) value of the government debt isconstant, then the conventionally:A) reported government budget will show a deficit equal to the inflation rate times theoutstanding debt.B) reported government budget will show a deficit equal to less than the inflation ratetimes the outstanding debt.C) reported government budget will be balanced.D) measured government budget will show a surplus equal to the inflation rate timesthe outstanding debt.17. Assume that the nominal interest rate is 11 percent, the inflation rate is 8 percent, andgovernment debt at the beginning of the year equals $4 trillion. By how much is the government budget deficit overstated as a result of inflation?A) $0.12 trillionB) $0.32 trillionC) $0.44 trillionD) $0.80 trillion18. A deficit adjusted for inflation should include only government spending used to make_____ interest payments.A) realB) nominalC) foreignD) domestic19. If the government debt, D, equals $5 trillion, the nominal interest rate is 7 percent, andthe real interest rate is 3 percent, then nominal budget deficit overstates the real deficit by $ ___ trillion.A) 0.35B) 0.20C) 0.15D) 0.0720. Current measures of the U.S. federal government's budget deficit account for all of thefollowing except:A) government expenditures.B) government revenues.C) changes in government indebtedness.D) changes in government capital assets.21. If capital budgeting procedures were employed, then a budget deficit would bemeasured as:A) the sum of government debt.B) the change in government debt.C) the change in government debt minus the change in government capital assets.D) the change in government capital assets.22. When the federal government incurs additional debt to acquire an asset, under currentbudgeting procedures the deficit ______, while under capital budgeting procedures the deficit ______.A) does not change; increasesB) increases; does not changeC) does not change; decreasesD) decreases; does not change23. Capital budgeting is a procedure that:A) adjusts the deficit for inflation.B) estimates what the deficit would be if the economy were operating at the naturalrate of output.C) accounts for assets as well as liabilities.D) measures the impact of fiscal policy on the lifetime incomes of individuals ofdifferent ages.24. Under capital budgeting, all of the following transactions would affect the federalbudget deficit except the federal government's:A) sending a check to a welfare recipient.B) sending a check to the state of Massachusetts.C) selling a highway to the state of New York and using the proceeds to retire federaldebt.D) selling an office building.25. The amount the government would owe if a borrower were to default on agovernment-guaranteed loan is an example of:A) capital budgeting.B) a contingent liability.C) a cyclically adjusted liability.D) Ricardian equivalence.26. One item that is considered part of the federal debt is:A) Treasury bills.B) future Social Security benefits.C) student loans, which may go into default.D) potential liabilities of savings and loan associations.27. The debt of the United States government is underreported in the view of manyeconomists because all of the following liabilities are excluded except:A) future pensions of government employees.B) debt owed to foreigners.C) future Social Security benefits.D) government guarantees of student loans.28. The cyclically adjusted budget deficit:A) adjusts the deficit for inflation.B) estimates what the deficit would be if the economy were operating at the naturalrate of output.C) accounts for assets as well as liabilities.D) measures the impact of fiscal policy on the lifetime incomes of individuals ofdifferent ages.29. An estimate of what government spending and tax revenue would be if the economywere operating at its natural rate of output and employment is called the ______ budget.A) cyclically adjustedB) inflation-adjustedC) capital-assetD) generational accounting30. Cyclically adjusted budgets are useful because they:A) systematically account for changes in government assets and liabilities.B) reflect policy changes, but not current economic conditions.C) account for tax burdens on different generations of taxpayers.D) correctly account for the impact of inflation on government indebtedness.31. Assume that a government has a balanced budget when the economy is at fullemployment. If the economy then enters a recession, with no change in tax or spending laws, then the budget of the government is most likely to:A) remain balanced.B) be in deficit.C) be in surplus.D) be in either deficit or surplus, depending on the severity of the recession.32. Each of the following changes would allow the measured budget deficit to provide atruer picture of fiscal policy except:A) correcting for the effects of inflation.B) offsetting changes in government liabilities with changes in government assets.C) excluding some liabilities altogether.D) correcting for the effects of the business cycle.33. Measuring the size of government debt is complicated by all of the following factorsexcept:A) inflation.B) uncounted liabilities.C) capital assets of the government.D) failure of the Office of Management and Budget to disclose figures on capitalexpenditures and credit programs.34. According to the traditional view of government debt, if taxes are cut without cuttinggovernment spending, then the long-run effects will be ______ steady-state capital and ______ consumption.A) higher; higherB) lower; lowerC) higher; lowerD) lower; higher35. According to the traditional view of government debt, if taxes are cut without cuttinggovernment spending, then the short-run effects will be:A) higher output and lower unemployment.B) higher output and higher unemployment.C) no change in output or unemployment.D) no change in output and higher unemployment.36. According to the traditional view of government debt, if taxes are cut without cuttinggovernment spending, then the international effect initially will be a capital ______ anda trade ______.A) inflow; deficitB) inflow; surplusC) outflow; deficitD) outflow; surplus37. According to the traditional view of government debt, if taxes are cut without a cut ingovernment spending, then in the United States this situation will lead to ______ net indebtedness on the part of the United States to foreign countries and ______ netexports.A) more; moreB) more; fewerC) less; fewerD) less; more38. The international impacts of a debt-financed tax cut, according to the traditional view ofgovernment debt, are a(n) ______ in net exports and a domestic currency _____.A) increase; appreciationB) increase; depreciationC) decrease; depreciationD) decrease; appreciation39. According to the traditional viewpoint of government debt, a tax cut without a cut ingovernment spending:A) stimulates consumer spending in the short run and reduces national saving.B) stimulates consumer spending in the short run and reduces private saving.C) has no effect on consumer spending but reduces national saving.D) has no effect on consumer spending but reduces private saving.40. According to the traditional viewpoint of government debt, a tax cut without a cut ingovernment spending:A) raises consumption in both the short run and the long run.B) lowers consumption in both the short run and the long run.C) raises consumption in the short run but lowers it in the long run.D) lowers consumption in the short run but raises it in the long run.41. According to the traditional view of government debt (as in the Mundell–Flemingmodel), if taxes are cut without cutting government spending, then the short-run effects are a(n) ______ of the dollar and a(n) ______ in net exports.A) appreciation; increaseB) appreciation; decreaseC) depreciation; increaseD) depreciation; decrease42. According to the traditional view of government debt (as in the IS–LM model), if taxesare cut without cutting government spending, then in the short run interest rates will ______ and investment will ______.A) increase; increaseB) increase; decreaseC) decrease; decreaseD) decrease; increase43. According to supply siders, tax cuts can raise total tax revenue if the tax cuts generatelarge enough:A) decrease in aggregate supply.B) increase in aggregate supply.C) decrease in the money supply.D) increase in the money supply.44. Government tax policy can affect aggregate supply as well as aggregate demand,because changes in taxes change the:A) supply of money in the economy.B) length of the inside lag of fiscal policy.C) incentives to work and invest.D) tradeoff between inflation and unemployment.45. Ricardian equivalence refers to the same impact of financing government:A) whether by printing money or raising taxes.B) in the long run as in the short run.C) whether by debt or taxes.D) in an open economy as in a closed economy.46. The logic of Ricardian equivalence implies that:A) tax cuts do not influence consumer spending but changes in government spendingdo.B) neither tax cuts nor changes in government spending affect consumer spending.C) tax cuts combined with future decreases in government spending will decreaseconsumer spending.D) if the government cuts taxes and increases current government spending, consumerspending will increase.47. According to the theory of Ricardian equivalence, if consumers are forward-looking,they will view a tax cut combined with no plans to reduce government spending as______, so their consumption will ______.A) additional disposable income; increase.B) additional disposable income; remain unchanged.C) a rescheduling of taxes into the future; increase.D) a rescheduling of taxes into the future; remain unchanged.48. According to the theory of Ricardian equivalence, tax cuts combined with no plans toreduce government spending ______ public saving and ______ private saving.A) reduce; reduceB) reduce; increaseC) increase; increaseD) increase; reduce49. A debt-financed tax cut will ______ saving in the traditional view and ______ saving inthe view of Ricardian equivalence.A) increase; increaseB) decrease; decreaseC) decrease; increaseD) decrease; not change50. A debt-financed tax cut will ______ current consumption in the traditional view and______ current consumption in the view of Ricardian equivalence.A) increase; increaseB) increase; decreaseC) increase; not changeD) decrease; decrease51. All of the following are arguments against Ricardian equivalence except:A) consumers make consumption decisions myopically.B) consumers are rational and forward-looking in consumption decision-making.C) consumers are borrowing-constrained.D) consumers do not expect future taxes to fall on them.52. Suppose a household considers only current income in making consumption decisions.This is an example of:A) Ricardian equivalence.B) the permanent-income hypothesis.C) myopia.D) the life-cycle model.53. The Ricardian view on fiscal policy makes less sense if people are:A) rational and practice foresight.B) shortsighted and not fully rational.C) able to plan for the future.D) able to borrow without constraint.54. In response to a tax cut, the consumption of a consumer who is borrowing-constrained______, whereas the consumption of a forward-looking, unconstrained consumer acting in accord with Ricardian equivalence ______.A) increases; increasesB) increases; remains unchangedC) remains unchanged; remains unchangedD) remains unchanged; increases55. When President George H. W. Bush lowered tax withholding in 1992 without loweringthe amount of taxes owed, surveys showed that:A) almost everyone spent the higher take-home pay.B) almost everyone saved the higher take-home pay.C) a majority of respondents said they would spend the higher take-home pay, but asignificant minority said they would save it.D) a majority of respondents said they would save the higher take-home pay, but asignificant minority said they would spend it.56. Given a reduction in income tax withheld, but no change in income tax owed,households that act according to Ricardian equivalence would ______ the extratake-home pay, while those facing binding borrowing constraints would ______ the extra-take home pay.A) spend; spendB) spend; saveC) save; saveD) save; spend57. Proponents of Ricardian equivalence argue that the relevant decision-making unit is the:A) individual.B) household.C) infinitely lived family.D) community.58. Proponents of Ricardian equivalence argue that if taxes are cut without cuttinggovernment spending and taxes are not expected to increase in the future until after an individual expects to be dead, then the individual will:A) spend all of the increase in income.B) spend some of the increase in income and save the rest.C) use the increase in income to buy government bonds to help finance the deficit.D) save all of the increase in income and leave it as a bequest to his or her children.59. From the Ricardian point of view, a consumer should not raise his or her consumptionwhen taxes are cut but government spending is not cut because:A) the government is going to raise taxes by exactly as much as the cut in the nextyear.B) the government is going to raise taxes by exactly as much as the cut plus interest inthe next year.C) the government is sure to raise taxes by an amount equal in present value to thedebt incurred this year, sometime in the taxpayer's lifetime.D) even if the government does not raise enough extra taxes during the taxpayer'slifetime to pay off, in present value, the debt incurred this year, the taxpayer shouldmake provision for the taxes that will be levied on his or her heirs.60. Assume that nobody cares about the economic well-being of future generations. Thenthe Ricardian equivalence view of the effect of debt-financed tax cuts is:A) totally invalid.B) still fully valid because the government has the option to levy taxes to pay off thefull debt in just a few years.C) still fully valid as long as the government cuts spending also.D) still partially valid because most of the taxpayers will live and pay taxes for asubstantial number of years after the tax cut.61. The strategic bequest motive hypothesizes that parents:A) leave bequests to children because they care about their children's well-being.B) leave bequests to children who are borrowing-constrained.C) make larger bequests the larger the quantity of taxes that will be shifted to theirchildren.D) use the threat of disinheritance to control their children's behavior.62. The experience of the 1980s:A) clearly contradicted the Ricardian equivalence view because national saving wasvery low.B) clearly supported the Ricardian equivalence view, for people saved little onlybecause they were optimistic, as confirmed by the stock market.C) will provide a clear answer on the validity of Ricardian equivalence as soon aseconomists are able to analyze it with their computers.D) may be used to argue both in favor of and against the Ricardian equivalence viewof the tax cuts.63. In the United States, having a balanced budget is currently enforced for:A) the federal government.B) no state governments.C) all state governments.D) many state governments.64. One reason for not requiring a balanced federal budget at all times is that with abalanced-budget rule:A) expenditures are not limited because, if the government wants to raiseexpenditures, it just raises taxes.B) in a recession even the automatic stabilizing powers of our system of taxes andtransfers could not work.C) the distorting features of the tax system are minimized.D) it is possible to shift the burden of a war from current to future generations.65. Tax smoothing is a desirable policy because it:A) reduces the distortions of incentives caused by taxes.B) reduces budget deficits in periods of recession.C) eliminates the impact of automatic stabilizers.D) is consistent with a balanced budget.66. One way to shift the tax burden from the current generation to future generations is tofinance a war:A) by raising taxes.B) by printing money.C) by running a budget surplus.D) by running a budget deficit.67. To minimize the disincentives of very high taxes, a policy of tax smoothing requires abudget ______ in years of unusually low government revenue and a budget ______ in years of unusually high government expenditures.A) surplus; deficitB) deficit; surplusC) surplus; surplusD) deficit; deficit68. Using fiscal policy, including automatic stabilizers, to stabilize output over a businesscycle is not consistent with:A) rational expectations.B) inflation targeting.C) the natural-rate hypothesis.D) a strict balanced-budget rule.69. A strict balanced-budget rule would:A) permit the use of fiscal policy for stabilization.B) allow the use of tax smoothing to reduce tax distortions.C) redistribute tax burdens across generations.D) restrain political incompetence and opportunism.70. Monetary policy is linked to fiscal policy when government spending is financed by:A) taxes.B) borrowing from banks.C) borrowing from foreigners.D) printing money.71. The real value of government debt is reduced by:A) expected inflation.B) expected deflation.C) unexpected inflation.D) unexpected deflation.72. Financing a budget deficit by ______ leads to inflation, and inflation ______ the realvalue of government debt.A) issuing debt; increasesB) issuing debt; decreasesC) printing money; increasesD) printing money; decreases73. Hyperinflations typically occur when governments:A) attempt to keep the unemployment rate below the natural rate.B) finance spending with the inflation tax.C) set inflation targets too high.D) use discretionary monetary policy to stabilize output.74. To force politicians to judge whether government spending is worth the costs, someeconomists have argued for:A) a balanced-budget rule for fiscal policy.B) a constant money-growth rule for monetary policy.C) avoiding the assumption of any contingent liabilities.D) the application of Ricardian equivalence.75. The possibility of capital flight is likely to be greater at higher levels of governmentdebt because there is a greater:A) temptation to default on the debt.B) likelihood that the government will begin issuing indexed bonds.C) probability that a balanced budget will be adopted by the government.D) potential for tax smoothing policies to be eliminated.76. High levels of government debt that raise investors' fear of a government default on debtwill result in capital ______ and a(n) ______ of the country's exchange rate.A) outflows; depreciationB) outflows; appreciationC) inflows; depreciationD) inflows; appreciation77. Indexed bonds produce all of the following benefits except:A) less inflation risk.B) more financial innovation.C) better government incentives.D) lower rates of inflation.78. A measure of the expected rate of inflation can be found by the:A) yield on nominal bonds plus the yield on index bonds.B) yield on nominal bonds minus the yield on index bonds.C) observed rate of inflation minus the yield on real bonds.D) observed rate of inflation minus the yield on nominal bonds.79. Inflation-indexed government bonds have all of the following benefits except:A) eliminating inflation.B) reducing the government's incentive to produce surprise inflation.C) encouraging financial innovation.D) eliminating inflation risk.80. If the government levies a one-time temporary tax on the young and gives the proceedsto the elderly, and both generations follow the life-cycle consumption pattern but are not altruistically linked:A) both the young and the old will consume more.B) there will be a net increase in overall consumption.C) there will be a net decrease in overall consumption.D) there will be no change in overall consumption.81. If the government levies a one-time temporary tax on the young and gives the proceedsto the elderly, and both generations follow the life-cycle consumption pattern and arealtruistically linked:A) both the young and the old will consume more.B) there will be a net increase in overall consumption.C) there will be a net decrease in overall consumption.D) there will be no change in overall consumption.82. If an individual should subtract the present value of future tax obligations due to thegovernment deficit from his or her disposable income, this situation suggests that, inaggregate analysis, the government deficit should be subtracted from disposable income.That is, instead of C = a + b(Y –T), we should use: C = a + b((Y –T – (G –T)), or = a + b(Y –G).a. Using this consumption function and the further relations:I = IG = GT = TY = C + I + Gwrite the equilibrium equation determining Y as a function of a, I, G, and T.b. If b equals 0.5, what are the numerical values of the multipliers for I, G, and T, respectiv83. Compare the traditional view versus the view of Ricardian equivalence of the effects ofa debt-financed tax cut on:a. national saving,b. current consumption, andc. the real interest rate.84. Many people are concerned about the budget deficit of the U.S. federal government.Suggest at least three possible negative economic effects of a budget deficit and threepossible economic benefits of a budget deficit.85. The U.S. Treasury reports the budget deficit or surplus of the federal government. Giveat least one reason why the measured budget deficit might overstate the “true” deficitand at least one reason the measured figure might understate the “true” deficit.86. Explain how tax cuts can affect both aggregate demand and aggregate supply.87. What is Ricardian equivalence? Give at least three reasons why Ricardian equivalencemight not correctly describe an economy.88. Countries seeking to adopt the euro as their currency must meet certain criteria,including the requirements to keep their government budget deficit equal to 3 percent or less of GDP, and to hold government debt levels below 60 percent of GDP. Discuss why there are fiscal policy criteria for joining a monetary union.89. Graphically illustrate the traditional view of the short-run impacts of a debt-financed taxcut on:a. interest rates and output in a closed economy in the short run, using the IS–LM model.b. exchange rates and output in a small open economy with a flexible exchange rate in therun, using the Mundell–Fleming model.90. Graphically illustrate the traditional view of the long-run impacts of a debt-financed taxcut on :a. saving, investment, and real interest rate using the classical model (Chapter 3).b. steady state capital per worker and output per worker using the Solow growth model.91. Using the model of aggregate demand–aggregate supply to illustrate the traditionalview, graphically compare the short-run and long-run impact of debt-financed tax cuts on:a. output,b. prices.92. War is the generator of debt burden for countries. How does war generate debt for acountry?。

短期经济波动的理论与政策短期经济如何波动，是宏观经济学研究的重要内容之一。

在众多解释短期经济波动的理论中，凯恩斯经济学派用总需求和总供给解释短期经济波动的理论，成为主流的短期经济波动理论。

该理论系统的阐述了货币政策和财政政策如何影响经济周期，以及从需求曲线和总供给曲线如何形成，各种政策如何通过影响总需求或者总供给来形成短期经济的均衡。

具体来说，可将该理论整理如下：一、经济周期的衡量在众多的经济指标中，国内生产总值（GDP）被认为是衡量总体经济状况的最概括的指标，它衡量经济的总收入和总支出。

GDP的增长变动，代表着经济的周期波动。

我们由GDP的核算课程中可以知道，国内生产总值=消费+投资+政府购买+净出口，即GDP=C+I+G+NX。

因此，GDP的增减变动，可以分解为消费、投资、政府购买和净出口的增减变动，分析GDP变动的原因，就可以分别分析消费、投资、政府购买和净出口的变动原因。

衡量经济运行好坏的另外一个指标是失业率。

短期经济繁荣的时候，就业人数增加，失业率就下降；反之，短期经济衰退时，失业人数增加，失业率上升。

因此，我们可以看到，失业率和GDP存在着一种负相关的关系，这种关系被称为奥肯定律。

以美国的经济数据为例子，通过计算失业率的变动和实际GDP的百分比变动之间的关系，得到一个函数：实际GDP的百分比变动=3%-2×失业率的变动该公式表明，对失业率增长的每一个百分点，实际GDP增长通常下降2%。

短期中，失业率和GDP的这种高度负相关关系，说明通过研究GDP的变动，可以大概掌握失业率的变动，这进一步说明GDP是衡量短期经济的最好指标。

因此，在短期中，我们以GDP作为衡量经济短期波动的指标。

在GDP核算中，我们知道GDP等于总收入，也等于总支出，在以后的分析中，GDP常以这两个名称出现。

二、短期经济的假设经济在短期和在长期是有差别的，其中最主要的差别表现在价格上。

宏观经济学假设，在长期，经济中的价格是具有弹性的，很灵活，能对供给或需求的变动做出反应。

腹有诗书气自华第4篇 经济周期理论：短期中的经济第9章 经济波动导论课后习题详解跨考网独家整理最全经济学考研真题，经济学考研课后习题解析资料库，您可以在这里查阅历年经济学考研真题，经济学考研课后习题，经济学考研参考书等内容，更有跨考考研历年辅导的经济学学哥学姐的经济学考研经验，从前辈中获得的经验对初学者来说是宝贵的财富，这或许能帮你少走弯路，躲开一些陷阱。

以下内容为跨考网独家整理，如您还需更多考研资料，可选择经济学一对一在线咨询进行咨询。

一、概念题1．奥肯定律（Okun ’s law ）答：奥肯定律是表示失业率与实际国民收入增长率之间关系的经验统计规律，由美国经济学家奥肯在20世纪60年代初提出。

其主要内容是：失业率每高于自然失业率1个百分点，实际GDP 将低于潜在GDP 2个百分点。

奥肯定律的一个重要结论是：实际GDP 必须保持与潜在GDP 同样快的增长，以防止失业率的上升。

如果政府想让失业率下降，那么，该经济社会的实际GDP 的增长必须快于潜在GDP 的增长。

根据奥肯的研究，在美国，失业率每下降1%，实际国民收入增长2%。

但应该指出的是：①奥肯定律表明了失业率与实际国民收入增长率之间是反方向变动的关系；②两者的数量关系1∶2是一个平均数，在不同的时期，这一比率并不完全相同；③这一规律适用于经济没有实现充分就业时的情况。

在经济实现了充分就业时，这一规律所表示的自然失业率与实际国民收入增长率之间的关系要弱得多，一般估算是1∶0.76。

2．领先指标（leading indicators ）答：领先指标是指一般先于整体经济变动的变量，可以帮助经济学家预测短期经济波动。

由于经济学家对前导指标可靠意见看法的不一致，导致经济学家给出不同的预测，其中就包括短期经济波动情况的预测。

领先指标的大幅度下降预示经济很可能会衰退，大幅度上升预示经济很可能会繁荣。

3．总需求（aggregate demand ）答：总需求是指整个经济社会在任何一个给定的价格水平下对产品和劳务的需求总量。

第一篇：理解以下概念：(1)模型：用来解释经济中GDP，通货膨胀，失业等这些经济变量，如供求模型。

(2)内生变量：是一个模型要解释的变量。

内生变量在模型之内决定，并作为模型的产出。

(3)外生变量：是一个模型给出最为既定的变量。

外生变量来自模型以外，并作为模型的投入。

(4)伸缩性：出清模型研究工资与物价关系的名称。

(5)粘性：出清模型研究工资与物价关系的名称。

(6)市场出清：物品的价格的迅速变动是供给量与需求量平衡。

即市场使供求平衡，叫市场出清。

P97页索洛模型表明，储蓄率是稳定状态资本存量的关键决定因素。

如果储蓄率高，经济就出现大量资本存量和高产出水平。

如果储蓄率低，经济就出现少量资本存量和低产出水平。

根据索洛模型，一国把大部分收入用于储蓄和投资，它将具有高稳定状态资本储量和高水平收入，费雪效应：名义利率=实际利率+通货膨胀率i=r+π卡甘模型：现在与未来货币如何影响物价水平，即如果实际货币余额需求量取决于持有货币的成本，那么物价水平就取决于现在货币供给和未来货币供给。

P187页公式A9（略）说明，信任对结束超速货币通胀是重要的NX=Y-(C+I+G) 即净出口=产出-国内支出（消费+投资+政府购买）从贸易平衡出发时，减少国民储蓄的财政政策变动引起贸易赤字。

实际汇率=(名义汇率×国内物品价格)/国外物品价格由此可以算出中国与美国的实际汇率是不一样的，但是可以知道现在美国物价相对来说是偏低的，肉类和中国差不多，蔬菜贵不少，其余的东西例如衣食住行中，衣服比中国便宜一些，吃饭比中国便宜，住的话贵一些，行的话自己开车便宜一些，但是遇到服务业的话，比中国贵不少，随便理发吃饭都要至少20刀，而在美国住就是住在一个大农场，20w刀，自己没车，打车那就贵了，要是自己有车，那就便宜，总的来说，美国的实际购买力比中国高5倍，现在要做的事情是，怎么样去提高自己的收入，不单单是靠工资，还要靠投资，这样才能挣到钱。