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A-level economics revision guides and question banks covering labour markets, supply and demand, market structure and all core economics a-level topics.

以下內容我們會持續更新：

今天帶給大家Alevel經濟筆記是：

第七章：勞動力市場——完全競爭勞動力市場中的均衡工資

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In the last two Learn-its, we looked at where the demand for labour and the supply of labour came from.

To find the equilibrium wage, as with the product market, we need to put these two concepts together.

For most industries, the equilibrium wage and quantity of labour employed will be determined where these two curves cross.

As we shall see, this is not necessarily the case for the monopsonist.

Lets start with the easy model of the perfectly competitive labour market.

在最后兩個 Learn-it 中，我們研究了勞動力需求和勞動力供應的來源。要找到均衡工資，就像產品市場一樣，我們需要將這兩個概念放在一起。對于大多數行業，均衡工資和就業勞動力數量將在這兩條曲線的交叉處確定。正如我們將看到的，壟斷者不一定是這種情況。讓我們從完全競爭勞動力市場的簡單模型開始。

The equilibrium wage in a perfectly competitive labour market

完全競爭勞動力市場中的均衡工資

The diagram below shows the equilibrium amount of labour employed, and the equilibrium wage, for the perfectly competitive industry and a firm in that industry.

下圖顯示了完全競爭行業和該行業公司的均衡就業勞動力數量和均衡工資。

We see the normal looking demand and supply curves in the industry diagram on the left.

The curves cross at point A, giving real wage W1 and labour employed L1.

Remember that there are so many firms in the industry that each firm has no control over the given wage rate.

Each firm can employ as much labour as it wants at the given real wage rate W1.

The amount they actually employ depends on their MRP curve (which is their demand curve for labour).

As we said earlier, they will maximise their profit if they employ l1 units of labour where MRP = MFC (which occurs at point B).

我們在左側的行業圖中看到“正常”的供需曲線。曲線在 A 點相交，給出實際工資 W 1和就業勞動力 L 1。請記住，行業中有如此多的公司，以至于每家公司都無法控制給定的工資率。在給定的實際工資率 W 1下，每個企業都可以雇傭盡可能多的勞動力。他們實際使用的數量取決于他們的 MRP 曲線（這是他們的勞動力需求曲線）。正如我們之前所說，如果他們雇用 l 1個單位的勞動力，其中 MRP = MFC（發生在 B 點），他們將最大化他們的利潤。

Shifts in the demand and supply curves 需求曲線和供給曲線的移動

An important part of the topic Supply and demand was the analysis of why the industry supply and demand curves might shift.

We must do the same here, but this time we are dealing with labour markets rather than product markets.

“供需”主題的一個重要部分是分析行業供需曲線為何會發生變化。我們必須在這里做同樣的事情，但這次我們處理的是勞動力市場而不是產品市場。

Shifts in demand需求變化

Just like with the product market, the demand for labour curve will only shift if one of the conditions of demand changes.

It will not shift just because the real wage rate itself changes.

就像產品市場一樣，只有當需求條件之一發生變化時，對勞動力的需求曲線才會移動。它不會僅僅因為實際工資率本身發生變化而發生變化。

Remember that the demand for labour curve is the MRP curve, which was, in turn, derived from the MPP curve.

If there is an improvement in labour productivity then this will mean that the workers will produce more at any given wage rate (and given the fixed amount of capital), and the MPP curve will shift to the right, shifting the MRP curve to the right.

請記住，勞動力需求曲線是 MRP 曲線，而 MRP 曲線又源自 MPP 曲線。如果勞動生產率有所提高，那么這將意味著在任何給定的工資率（以及給定的固定資本量）下，工人將生產更多，并且 MPP 曲線將向右移動，MRP 曲線將向右移動.

Also remember that the MRP curve was derived from the MPP times the price.

So, if the price of the good being produced changes, then this will change the MRP at all wage levels and the MRP curve will shift.

還要記住，MRP 曲線是從 MPP 乘以價格得出的。因此，如果所生產商品的價格發生變化，那么這將改變所有工資水平的 MRP，并且 MRP 曲線將會移動。

In a similar way to the product market, where the change in the price of a substitute can shift the demand curve, if the price of, say, capital rises (a substitute for labour), then the demand curve for labour will shift to the right.

與產品市場類似，替代品價格的變化可以移動需求曲線，如果資本價格上升（勞動力的替代品），那么勞動力的需求曲線將移動到正確的。

We can see how these shifts will affect the equilibrium wage and labour employed. The initial equilibrium is wage W1 and labour L1.

If, for example, there were an improvement in the productivity levels of the workers in an industry (more efficient use of labour through shift work perhaps), then the labour demand curve (MRP curve) would shift to the right, causing a rise in the real wage rate to W2 and a rise in numbers employed to L2.

我們可以看到這些變化將如何影響均衡工資和就業勞動力。初始均衡是工資 W 1和勞動力 L 1。例如，如果一個行業的工人的生產率水平有所提高（可能通過輪班工作更有效地利用勞動力），那么勞動力需求曲線（MRP 曲線）將向右移動，導致實際工資率增加到 W 2和就業人數增加到 L 2。

What if the price of the good being produced fell (due to a fall in real incomes and a shift to the left of the product demand curve perhaps)?

This would make the value of MRP fall for all wage levels, and so the labour demand curve would shift to the left, giving wage W3 and labour employed L3.

如果生產的商品價格下降（可能是由于實際收入下降和產品需求曲線向左移動）怎么辦？這將使所有工資水平的 MRP 值下降，因此勞動力需求曲線將向左移動，從而得到工資 W 3和雇傭勞動力 L 3。

Shifts in supply供應變化

One of the reasons is fairly obvious; the other is a bit subtler.

The obvious one is if the is simply an increase in the number of people in the economy available to work in the given industry.

This could be because of an increase in net immigration, a change in the demographics of the economy or due to government policy, like the New Deal. These increases in numbers will shift the supply of labour curve to the right.

原因之一是相當明顯的；另一個有點微妙。顯而易見的是，如果這僅僅是經濟中可在特定行業工作的人數的增加。這可能是因為凈移民的增加、經濟人口結構的變化或政府政策（如新政）。這些數量的增加將使勞動力供給曲線向右移動。

A less obvious cause is the situation in other industries.

If, in relative terms, the wage rate becomes less attractive in a similar industry, or the working conditions deteriorate, then the industry in question will experience an increase in the number of workers offering their labour services. This will shift the supply of labour curve to the left.

一個不太明顯的原因是其他行業的情況。如果相對而言，類似行業的工資率變得不那么有吸引力，或者工作條件惡化，那么相關行業提供勞務的工人數量將會增加。這將使勞動力供給曲線向左移動。

In the diagram above, you can see what happens to the equilibrium when the supply curve shifts. A shift to the right causes the real wage rate to fall (from W1 to W2) and the numbers employed to rise (from L1 to L2).

A shift to the left causes the real wage rate to rise (from W1 to W3) and the numbers employed to fall (from L1 to L3).

在上圖中，您可以看到當供給曲線移動時均衡會發生什么。向右移動會導致實際工資率下降（從 W 1到 W 2）和就業人數上升（從 L 1到 L 2）。向左移動會導致實際工資率上升（從 W 1到 W 3）而就業人數下降（從 L 1到 L 3）。

The equilibrium wage in monopsony

壟斷企業的均衡工資

Before we get going, it should be noted that labour markets might be imperfect due to there being only one seller of labour as well as the case covered here, the monopsonist buyer of labour (one buyer of labour - the employer).

The best example of a situation where there is only one seller of labour is where a trade union manages to control the amount of labour available to the employer.

This special case is covered in the Learn-it called Trade unions.

在我們開始之前，應該注意勞動力市場可能是不完善的，因為只有一個勞動力賣方以及這里所涵蓋的情況，即勞動力的壟斷買方（勞動力的一個買方 - 雇主）。只有一個勞動力賣方的情況的最好例子是工會設法控制雇主可用的勞動力數量。這種特殊情況包含在稱為“工會”的 Learn-it 中。

Look at the diagram above. You should recognise the supply curve and the MFC curve, which is above the supply curve.

Remember that the marginal cost of employing an extra worker for the monopsonist is much higher than the actual wage offered (which is read off the supply curve).

In attracting the extra worker, the slight rise in the real wage rate has to be paid to all the existing workers, on top of the wage that is paid to the new worker.

看上面的圖表。你應該認識供給曲線和高于供給曲線的 MFC 曲線。請記住，為壟斷者雇用額外工人的邊際成本遠高于提供的實際工資（從供給曲線中讀取）。為了吸引額外的工人，除了支付給新工人的工資之外，還必須支付給所有現有工人的實際工資率的小幅上漲。

The demand curve has been added. Ignoring the MFC curve for the minute, where would the equilibrium be if this labour market were perfectly competitive?

Where the supply and demand curves cross (point C), giving a wage of W2 and employment L2.

添加了需求曲線。暫時忽略 MFC 曲線，如果這個勞動力市場完全競爭，均衡會在哪里？在供給曲線和需求曲線相交的地方（C 點），工資為 W 2，就業為 L 2。

Now consider the monopsonist. He will maximise profit at the point where MRP = MFC (just like MC = MR in the product market).

This occurs at point A, but the real wage rate will not be W3. The real wage rate is read off the supply curve (of average factor cost curve), giving W1.

Do you remember that we said earlier that this diagram is the reflection of the monopolists product market diagram? If you think about it, the point where MC = MR on the product diagram is below the demand curve from which the price is obtained.

The same is going on here but upside down!

The point where MRP = MFC on the labour diagram is above the supply curve from which the wage is obtained.

The two sentences are the same except for the bits in italics.

現在考慮壟斷者。他將在 MRP = MFC（就像產品市場中的 MC = MR）處最大化利潤。這發生在 A 點，但實際工資率不會是 W 3。實際工資率是從供給曲線（平均要素成本曲線）中讀出的，給出 W 1。還記得我們之前說的這個圖是壟斷者產品市場圖的反映嗎？如果您考慮一下，產品圖上MC = MR的點位于獲得價格的需求曲線下方。這里也發生了同樣的事情，但顛倒了！勞動圖上MRP = MFC的點位于供給曲線上方從中獲得工資。除了斜體字外，這兩個句子是相同的。

The implication of all this is that the monopsonist pays a lower wage (W1 < W2) and employs fewer workers (L1 < L2) than if the industry had a perfectly competitive labour market.

Also, the monopsonist is paying its workers at a rate that is below their marginal revenue products.

In other words, it is paying them less than they are worth to the monopsonist.

The distance AB is the difference between what the last worker earned for the monopsonist in terms of revenue (the MRP) and what he was actually paid (W1).

The workers are being exploited!

所有這一切的含義是，與行業有完全競爭的勞動力市場相比，壟斷者支付的工資更低（W 1 < W 2）并且雇用的工人更少（L 1 < L 2 ）。此外，壟斷者以低于其邊際收益產品的比率支付工人工資。換句話說，它支付給他們的報酬低于壟斷者的價值。距離 AB 是最后一個工人為壟斷者賺取的收入（MRP）與他實際得到的報酬（W 1）之間的差值。工人被剝削！

Transfer earnings and economic rent

轉移收益和經濟租金

These are two important concepts, which, in a sense, are quite similar to the concepts of consumer surplus and producer surplus in the product market.

這是兩個重要的概念，在某種意義上與產品市場中的消費者剩余和生產者剩余的概念非常相似。

Defined formally, transfer earnings are the minimum earnings required for a unit of labour to stay in its present use.

Economic rent refers to any earnings over and above a workers transfer earnings.

The best way to explain these concepts is to use a diagram.

正式定義，轉移收入是一單位勞動維持其當前用途所需的最低收入。經濟租金是指超過工人轉移收入的任何收入。解釋這些概念的最好方法是使用圖表。

In the diagram above, you can see the normal looking demand and supply curves.

The equilibrium occurs at point A, giving a real wage rate of W2 and employment L2.

在上圖中，您可以看到“正常”的供需曲線。均衡發生在 A 點，實際工資率為 W 2，就業率為 L 2。

The upward sloping supply curve implies that as the real wage rate rises, more and more workers are prepared to offer their labour services.

As the real wage rate reaches W1, the 50th worker is just prepared to work for that real wage rate.

W1, therefore, represents the minimum amount for which the 50th worker is prepared to work in this industry.

It is his transfer earnings.

If he earned any less he would transfer his labour services to another use (a different job).

At the equilibrium wage W2, 100 workers are employed.

This means that the 100th worker was only just attracted into the industry.

Again, this is his transfer earnings.

向上傾斜的供給曲線意味著隨著實際工資率的上升，越來越多的工人準備提供他們的勞務服務。當實際工資率達到 W 1時，第 50個工人剛剛準備為該實際工資率工作。因此，W 1代表第 50名工人準備在該行業工作的最低金額。這是他的轉會收入。如果他掙得少了，他就會把他的勞務轉移到“另一種用途”（不同的工作）。在均衡工資 W 2下，雇傭了 100 名工人。這意味著第 100 名工人只是剛剛被吸引到這個行業。再說一次，這是他的轉移收益。

Given that the equilibrium wage is W2, the 50th worker is doing quite well.

He was prepared to work in this industry for W1, but he is being paid W2.

The extra that he is earning over and above W1 is his economic rent (represented by the distance CD, or W2 - W1).

假設均衡工資是 W 2，第 50個工人的工作做得很好。他準備為 W 1在這個行業工作，但他的報酬是 W 2。他在 W 1之外賺取的額外收入是他的經濟租金（由距離 CD 或 W 2 - W 1表示）。

If we extend all of this analysis to all real wage rates, then total transfer earnings is represented by the green trapezium and total economic rent is represented by the blue triangle.

如果我們將所有這些分析擴展到所有實際工資率，則總轉移收入由綠色梯形表示，總經濟租金由藍色三角形表示。

So what is the main determinant of transfer earnings and economic rent?

It should be clear from the diagram that the elasticity of the supply curve is crucial.

If the supply curve was very flat (elastic), then the blue triangle would be very small and the green trapezium would be very large.

The opposite would occur if the supply curve were very steep.

那么轉會收益和經濟租金的主要決定因素是什么？從圖中可以清楚地看出，供給曲線的彈性至關重要。如果供給曲線非常平坦（有彈性），那么藍色三角形會非常小，而綠色梯形會非常大。如果供給曲線非常陡峭，則會發生相反的情況。

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今天的Alevel經濟筆記就更新到這里，如果大家對Alevel經濟學感興趣可以關注我們，

關于Alevel經濟筆記第7章：勞動力市場后續的更新計劃如下：