The Trade-off between Unemployment and Inflation | 失业与通货膨胀的权衡关系

📚 The Trade-off between Unemployment and Inflation | 失业与通货膨胀的权衡关系

The relationship between unemployment and inflation is one of the most debated topics in macroeconomics. For decades, policymakers believed that a lower unemployment rate could be “bought” at the cost of higher inflation, and vice versa. This trade-off is captured by the Phillips curve, a key model in the CIE A-Level Economics syllabus. This article explores the short-run and long-run nature of the trade-off, the role of expectations, and its policy implications.

失业与通货膨胀之间的关系是宏观经济学中最具争议的话题之一。数十年来，政策制定者相信，较低失业率可以通过牺牲较高通货膨胀来“换取”，反之亦然。这一权衡关系由菲利普斯曲线所概括，它是CIE A-Level经济学考纲中的关键模型。本文探讨短期与长期权衡的性质、预期的作用及其政策含义。

1. Introduction to the Trade-off | 权衡关系导论

In the short run, an expansionary aggregate demand (AD) policy can shift the economy along a Phillips curve. When AD rises, firms hire more workers, unemployment falls, but the resulting pressure on wages and prices pushes inflation up. Conversely, contractionary policy reduces inflation but raises unemployment. This inverse relationship was first observed by A.W. Phillips in 1958 using UK wage data.

在短期内，扩张性总需求（AD）政策会使经济沿着菲利普斯曲线移动。当AD上升时，企业雇佣更多工人，失业率下降，但由此对工资和价格产生的压力推高通胀。相反，紧缩性政策会降低通胀，但提高失业率。这种反向关系最早由菲利普斯于1958年利用英国工资数据观察到。

For CIE Economics, the trade-off is usually illustrated with a downward-sloping Phillips curve. It suggests that governments face a policy dilemma: they cannot simultaneously achieve low unemployment and low inflation in the short run.

对于CIE经济学，权衡关系通常用一条向右下方倾斜的菲利普斯曲线来展示。它表明政府面临政策两难：短期内无法同时实现低失业和低通胀。

2. The Original Phillips Curve | 原始菲利普斯曲线

The original Phillips curve plotted the rate of change of money wage rates against the unemployment rate. It showed a stable, inverse relationship: when unemployment was low, wage growth was high; when unemployment was high, wage growth was low.

原始菲利普斯曲线将货币工资变动率与失业率绘制在一起，显示出稳定的反向关系：当失业率低时，工资增长率高；当失业率高时，工资增长率低。

Because wages are a major cost of production, the wage inflation curve can be converted into a price inflation curve by assuming prices are set as a mark-up over costs. Thus, the trade-off was extended to general inflation.

由于工资是生产成本的主要部分，通过假设价格是成本加成设定的，可以将工资通胀曲线转化为价格通胀曲线。因此，这一权衡被扩展到总体通胀。

This simple model implied that there was a stable menu of policy choices. A government could “pick” a point on the curve, trading off some inflation for less unemployment. During the 1960s, many policymakers accepted this idea and used demand management to keep unemployment low.

这一简单模型意味着存在一组稳定的政策选择菜单。政府可以在曲线上“选取”一点，用一些通胀换取更低的失业。在20世纪60年代，许多政策制定者接受这一观点，并使用需求管理来维持低失业率。

3. How the Trade-off Works | 权衡如何运作

The mechanism relies on sticky wages and sticky prices. In the short run, workers may not immediately anticipate or negotiate higher money wages when inflation rises. Firms, facing lower real wages, increase employment. Unemployment falls while inflation accelerates.

该机制依赖于黏性工资和黏性价格。短期内，当通胀上升时，工人可能不会立即预期或谈判更高的货币工资。企业面对实际工资下降，会增加雇佣。失业率下降而通胀加速。

In an AD–AS diagram, an outward shift of AD moves the economy along the short-run aggregate supply (SRAS) curve. Real output rises above potential, unemployment falls below the natural rate, and the price level rises faster. The corresponding point on a Phillips curve shows lower unemployment and higher inflation.

在AD-AS图中，AD曲线外移使经济沿着短期总供给（SRAS）曲线移动。实际产出高于潜在水平，失业率低于自然失业率，物价水平上升更快。在菲利普斯曲线上对应点显示较低失业和较高通胀。

This trade-off exists because workers and firms adjust their expectations slowly. If they had complete and immediate information, real wages would adjust and there would be no extra employment creation.

这种权衡之所以存在，是因为工人和企业调整预期缓慢。如果他们拥有完全且及时的信息，实际工资会调整，就不会产生额外就业创造。

4. The Role of Expectations | 预期的作用

By the late 1960s, economists such as Milton Friedman and Edmund Phelps criticised the original Phillips curve for ignoring inflation expectations. They argued that the trade-off exists only when expectation is adaptive and lags behind actual inflation.

到20世纪60年代末，弗里德曼和费尔普斯等经济学家批评原始菲利普斯曲线忽略了通胀预期。他们认为，只有当预期是适应性的且滞后于实际通胀时，权衡才存在。

An expectations-augmented Phillips curve can be written as:

一个附加预期的菲利普斯曲线可以写成：

π = πᵉ – α(u – uₙ)

where π is the actual inflation rate, πᵉ is the expected inflation rate, u is the unemployment rate, uₙ is the natural rate of unemployment, and α is a positive constant. When actual inflation exceeds expected inflation, unemployment falls below the natural rate.

其中π是实际通胀率，πᵉ是预期通胀率，u是失业率，uₙ是自然失业率，α是正常数。当实际通胀率高于预期通胀率时，失业率低于自然失业率。

If policymakers try to hold unemployment below uₙ, workers who observe higher prices will revise upward their expectations. The short-run Phillips curve shifts to the right, and the economy experiences higher inflation for the same level of unemployment.

如果政策制定者试图将失业率维持在uₙ之下，观察到价格上升的工人会向上修正预期。短期菲利普斯曲线右移，经济在相同失业率下经历更高通胀。

5. The Long-Run Phillips Curve | 长期菲利普斯曲线

In the long run, expectations fully adjust to actual inflation. When π = πᵉ, the equation implies that u = uₙ. Therefore, the long-run Phillips curve is vertical at the natural rate of unemployment. There is no trade-off between unemployment and inflation in the long run.

在长期，预期完全调整到实际通胀。当π = πᵉ时，方程意味着u = uₙ。因此，长期菲利普斯曲线在自然失业率处是垂直的。长期内失业与通胀之间不存在权衡关系。

This vertical curve means that expansionary monetary or fiscal policy can only raise inflation permanently, not reduce unemployment below its natural rate. The natural rate itself is determined by structural factors such as labour market flexibility, search frictions, and benefit systems.

这条垂直曲线意味着扩张性货币或财政政策只能永久性提高通胀，而不能将失业率降低到自然率之下。自然失业率本身由劳动力市场灵活性、搜寻摩擦和福利制度等结构性因素决定。

In the AD–AS diagram, the long-run aggregate supply (LRAS) is vertical. Any attempt to push output above potential will result in rising prices but no increase in real output. This aligns with the vertical long-run Phillips curve.

在AD-AS图中，长期总供给（LRAS）是垂直的。任何试图将产出推高至潜在水平之上的政策都会导致物价上涨，但实际产出不增加。这与垂直的长期菲利普斯曲线一致。

6. The Natural Rate of Unemployment | 自然失业率

The natural rate of unemployment (uₙ), also called the non-accelerating inflation rate of unemployment (NAIRU), is the rate at which inflation is stable. At this rate, the labour market is in equilibrium and inflation expectations are fully incorporated into wage bargains.

自然失业率（uₙ），又称非加速通货膨胀失业率（NAIRU），是指通货膨胀保持稳定的失业率。在该失业率下，劳动力市场处于均衡，通胀预期被完全纳入工资谈判。

Structural, frictional and voluntary unemployment constitute the natural rate. Cyclical unemployment is zero at uₙ. If unemployment lies below uₙ, inflation tends to rise; if above uₙ, inflation tends to fall.

结构性、摩擦性和自愿性失业构成自然失业率。在uₙ时，周期性失业为零。如果失业率低于uₙ，通胀趋于上升；如果高于uₙ，通胀趋于下降。

For A-Level analysis, students should distinguish between the short-run trade-off and the long-run vertical curve. The natural rate is not fixed; it may change due to supply-side policies, demographics, or institutional changes.

对于A-Level分析，学生应区分短期权衡和长期垂直曲线。自然失业率并非固定不变；它可能因供给侧政策、人口结构或制度变化而改变。

7. Policy Implications | 政策含义

The trade-off creates a short-run policy trade-off between inflation and unemployment. Governments and central banks often use demand-side policies to stabilise the economy. If the economy is booming with unemployment below the natural rate, policymakers may raise interest rates to reduce inflation, accepting a rise in unemployment. Conversely, during a recession, they may cut interest rates to reduce unemployment, accepting higher inflation.

这一权衡在短期内造成了通胀与失业之间的政策取舍。政府和央行通常使用需求侧政策稳定经济。如果经济繁荣，失业率低于自然失业率，政策制定者可能加息以降低通胀，同时接受失业率上升。相反，在衰退期间，可能降息以减少失业，接受更高通胀。

However, if policymakers attempt to exploit the trade-off persistently, expectations adjust and the short-run Phillips curve shifts. The result is stagflation – higher inflation and higher unemployment simultaneously. This was seen in the 1970s when oil shocks combined with expansionary policies.

然而，如果政策制定者持续利用这种权衡，预期会调整，短期菲利普斯曲线会发生移动。结果就是滞胀——高通胀与高失业同时出现。20世纪70年代石油冲击与扩张性政策结合时便曾出现这种情况。

Credibility of the central bank matters. If agents believe the bank will not tolerate inflation above target, inflation expectations remain anchored, making the short-run trade-off more favourable.

中央银行的信誉至关重要。如果公众相信央行不会容忍通胀高于目标，通胀预期就会保持锚定，从而使短期权衡更为有利。

8. Limitations and Criticisms | 局限与批评

The Phillips curve has been criticised on several grounds. First, the original stable trade-off disappeared in many countries, breaking down due to supply shocks. Second, the concept of a unique natural rate is questioned: hysteresis suggests that prolonged high unemployment may raise the natural rate permanently.

菲利普斯曲线在多个方面受到批评。第一，原始稳定的权衡关系在许多国家消失，因供给冲击而瓦解。第二，唯一自然失业率的概念受到质疑：滞后效应表明长期高失业可能永久性提高自然失业率。

Rational expectations theory goes further, arguing that if agents anticipate policy changes, even the short-run trade-off may be absent. Workers and firms use all available information to form forecasts, so systematic policy cannot fool them.

理性预期理论更进一步，认为如果代理人预期到政策变化，甚至短期权衡也可能不存在。工人和企业利用所有可得信息形成预测，系统性的政策无法欺骗他们。

Moreover, inflation is not purely a monetary phenomenon in open economies. Cost-push factors, such as commodity prices and exchange rates, can affect inflation independently of unemployment. Thus, the simple inverse relationship is often obscured in reality.

此外，在开放经济中，通胀并非纯粹是货币现象。商品价格和汇率等成本推动因素可以独立于失业率影响通胀。因此，简单的反向关系在现实中往往被掩盖。

9. The Trade-off in Practice: Stagflation | 实践中的权衡：滞胀

Stagflation refers to a combination of rising inflation and rising unemployment, which contradicts the original Phillips curve. In the 1970s, OPEC oil price shocks increased production costs, shifting the SRAS left. Output fell, unemployment rose, and the price level jumped.

滞胀是指通胀上升与失业上升并存，这与原始菲利普斯曲线相矛盾。20世纪70年代，OPEC石油价格冲击提高了生产成本，使SRAS左移。产出下降，失业上升，物价水平跳涨。

In the Phillips curve framework, the short-run curve shifted to the right. Any given unemployment rate was associated with a higher inflation rate, and vice versa. This showed that supply shocks can break the stable trade-off.

在菲利普斯曲线框架中，短期曲线向右移动。任何给定的失业率都对应更高的通胀率，反之亦然。这表明供给冲击可以打破稳定的权衡关系。

Policymakers were forced to choose between accepting higher unemployment or higher inflation, or using incomes policies to break inflationary expectations. The episode highlighted the importance of expectations and supply-side factors.

政策制定者被迫选择接受更高的失业率还是更高的通胀率，或者使用收入政策打破通胀预期。这一事件凸显了预期和供给侧因素的重要性。

10. Modern Perspectives | 现代观点

Since the 1990s, many central banks adopted inflation targeting. By committing to a low inflation target, they anchor inflation expectations. As a result, the short-run Phillips curve has become flatter or less stable. Empirical research shows that the trade-off may vary over time and across countries.

自20世纪90年代以来，许多央行采用通胀目标制。通过承诺低通胀目标，它们锚定了通胀预期。结果，短期菲利普斯曲线变得更平坦或更不稳定。实证研究表明，权衡关系可能随时间和国家而变化。

Globalisation, technology and labour market reforms have reduced the responsiveness of wages to unemployment. This implies a flatter Phillips curve, meaning larger changes in unemployment are needed to achieve a given change in inflation.

全球化、技术进步和劳动力市场改革降低了工资对失业的反应程度。这意味着菲利普斯曲线更平坦，即需要更大的失业变化才能实现给定的通胀变化。

Recent data from advanced economies show a “missing deflation” after the 2008 financial crisis and “missing inflation” after the post-pandemic recovery. These puzzles challenge the simple Phillips curve and suggest that expectations and other structural forces are crucial.

发达经济体近期数据显示，2008年金融危机后的“通缩缺失”和后疫情复苏中的“通胀缺失”现象。这些谜题挑战了简单的菲利普斯曲线，表明预期及其他结构性力量至关重要。

11. Evaluation for A-Level | A-Level评估要点

To reach high marks in CIE Economics, students should evaluate the trade-off by:

为了在CIE经济学中取得高分，学生应对这一权衡进行评估：

• Distinguishing short-run from long-run: the trade-off exists in the short run but is vertical in the long run. (区分短期与长期：权衡在短期存在，但在长期垂直。)
• Recognising the role of expectations: adaptive versus rational expectations change the effectiveness of policy. (认识预期的作用：适应性预期与理性预期改变政策有效性。)
• Considering supply-side factors: shocks can shift the Phillips curve, creating stagflation. (考虑供给侧因素：冲击会使菲利普斯曲线移动，造成滞胀。)
• Assessing the natural rate hypothesis: whether the natural rate is stable or subject to hysteresis. (评估自然率假说：自然失业率是否稳定或存在滞后效应。)
• Using real-world examples, such as the 1970s stagflation or the Volcker disinflation in the US, to illustrate policy trade-offs. (使用实际案例，如20世纪70年代滞胀或美国沃尔克反通胀，来说明政策取舍。)

A balanced conclusion might state that the Phillips curve is a useful short-run tool but offers little guidance for long-run policy. The best long-run strategy is to maintain credibility and low inflation expectations, while using supply-side policies to reduce the natural rate of unemployment.

一个平衡的结论可以指出，菲利普斯曲线在短期内是有用的工具，但对长期政策指导有限。最好的长期策略是保持信誉和低通胀预期，同时使用供给侧政策降低自然失业率。

12. Conclusion | 结论

The trade-off between unemployment and inflation is central to macroeconomic policymaking. The original Phillips curve suggested a stable menu of choices, but the expectations-augmented model showed that the trade-off is only temporary. In the long run, unemployment returns to the natural rate and the Phillips curve is vertical.

失业与通货膨胀之间的权衡是宏观经济政策制定的核心。原始菲利普斯曲线提供了一种稳定的选择菜单，但附加预期的模型表明权衡只是暂时的。长期来看，失业率回归自然失业率，菲利普斯曲线垂直。

For CIE A-Level students, understanding the Phillips curve requires careful distinction between short-run and long-run, the role of expectations, and the impact of supply shocks. Ultimately, while unemployment and inflation may trade off in the short run, sustainable non-inflationary growth depends on structural policies and credible monetary institutions.

对于CIE A-Level学生，理解菲利普斯曲线需要仔细区分短期与长期、预期的作用以及供给冲击的影响。最终，尽管失业与通胀在短期内可能互相权衡，但可持续的非通胀增长依赖于结构性政策和可信的货币制度。

Published by TutorHao | Economics Revision Series | aleveler.com

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