ALEVEL微观经济很重要的10张图 帮你速成画图小能手

图表题是ALEVEL经济考试最重要的得分点之一，但偏偏又是很多同学最“孩怕”的题型。今天就带大家理清考ALEVEL微观经济一定要知道的10张图，帮助你理解关键图表，加快解题速度，争取让图表题成为你的加分题型。

ALEVEL经济考试形式

以CIE考试局为例，考试一共有两张试卷，分别为Paper 1和Paper 2。

Paper 1 是选择题（Mutiple Choice)。Paper 2 是 数据分析与论文（Data Response)。 paper1选择题一共有3套试卷，考试时间60分钟。

每套试卷一共30道题，总分30，题目分为ALEVEL微观经济部分和宏观部分。其中，微观部分一般是15-18道题，宏观部分一般是12-15道题。 

AS经济学Paper 2也有3套试卷，其中的Data Response部分是给你一篇与经济相关的材料，绝大部分是来自新闻媒体。让你根据这篇材料回答4-5-6个小问题。当然，这部分表面上脱离了课本知识，实际上还是根据所学知识回答相关问题，侧重考查学员灵活运用知识的能力，对阅读能力也有一定要求。

ALEVEL微观经济

最重要的10张图

1. The law of diminishing returns

In the short run, the law of diminishing returns state that as we add more units of a variable input(i.e.labour or raw materials) to fixed amounts of land and capital, the change in the output will at first rise then fall.

大家可以从Marginal Product的角度来想，比如假设其他变量不变然后增加Labour的数量，刚开始MP会增加，但后来员工越来越多造成拥挤，MP会慢慢地下降，Total output会上升但是斜率在慢慢下降。

2. Fixed and Variable Costs in the short run

关于FC和VC的要点：

1. Fixed costs are independent of output and must be paid out even if the production stops.

2. Capital-intensive industries with a high ratio of fixed to variable costs scope for economies of scale.

3. AFC=Fixed Costs(FC)/Output(Q).

4. Marginal costs(MC) cuts both AVC and ATC at the minimum point of each.(Draw accurately!)

3. Economies of scale/Diseconomies of scale

In the long run, all factors of production are variable. How the output of a business responds to a change in factor inputs is called returns to scale. Economies of scale arethe cost advantages exploited by expanding the scale of production in the long run.The effect is to reduce long run average costs over a range of output.

这里大家需要知道的还包括diseconomies of scale的原因：

1. Control – monitoring the productivity and the quality of output from thousands of employees in big, complex corporations is imperfect and expensive–this links to the concept of the principal-agent problem i.e. the difficulties of shareholders monitoring the performance of managers.

2. Co-ordination - it can be difficult to co-ordinate complicated production processes across several plants in different locations and countries. Achieving efficient flows of information in large businesses is expensive as is the cost of managing supply contracts with hundreds of suppliers at different points of an industry’s supply chain.

3. Co-operation - workers in large firms may develop a sense of alienation and loss of morale. If they do not consider themselves to be an integral part of the business, their productivity may fall leading to wastage of factor inputs and higher costs

4. Natural Monopoly and Economic Efficiency

A natural monopoly occurs in an industry where LRAC falls over a wide range of output levels such that there may be room only for one supplier to fully exploit all of the internal economies of scale, reach the minimum efficient scale and therefore achieve productive efficiency.

The major utilities such as gas, electricity and water are often put forward as examples of industries with strong "natural tendencies" towards being a natural monopoly in part because of the huge fixed costs of building and maintaining nationwide networks / infrastructures of cables and pipes.

Key Point: A natural monopoly is characterised by increasing returns to scale at all levels of output – thus the long run cost per unit (LRAC) will drift lower as production expands. LRAC is falling because long run marginal cost is below LRAC.

5. Average, marginal and total revenue

需要注意的是MR和AR的位置，AR在上，MR在下。

6. Different objectives of businesses-effect on price, output and profit

需要注意的是Profit Max Output是在MC=MR

Revenue Max Output是在MR=0的点上

7. The shut down price for a business in the short run

In the short run the firm will continue to produce as long as total revenue covers total variable costs or put another way, so long as price per unit > or equal to average variable cost (AR = AVC).

The reason for this is as follows. A business’s fixed costs must be paid regardless of the level of output. If we make an assumption that these costs are sunk costs (i.e. they cannot be covered if the firm shuts down) then the loss per unit would be greater if the firm were to shut down, provided variable costs are covered.

In the short run, the supply curve for a competitive firm is the marginal cost curve above average variable cost.

8. Short run and long run in perfect competition

Key Point：No barriers to entry and super normal profits encourage the entry of new firms shifting market supply&price downward until price falls back to P2. Normal profits are restored.

就算公司在短期内盈利，perfect competition的条件下，新公司的进入带来market suppy增加，长期的话公司只会不盈利也不亏损。

9. Short Run and long run in monopolistic competition

A. Short-Run super normal profits

B. Long run price and output equilibrium with monopolistic competition

In the long run, normal profits are made; average and marginal revenue is affected by the entry of newproducts into the market

10. Oligopoly-the kinked demand curve model

An oligopoly is a market dominated by a few producers, each of which has control over the market. It is an industry where there is a high level of market concentration. However, oligopoly is best defined by the conduct (or behaviour) of firms within a market rather than its market structure.

The kinked demand curve model assumes that a business might face a dual demand curve for its product based on the likely reactions of other firms in the market to a change in its price or another variable. The common assumption is that firms in an oligopoly are looking to protect and maintain market share and that rival firms are unlikely to match another’s price increase but may match a price fall. I.e. rival firms within an oligopoly react asymmetrically to a change in the price of another firm.

The kinked demand curve model therefore makes a prediction that a business might reach a stable profit-maximising equilibrium at price P1 and output Q1 and have little incentive to alter prices. Even a shift in the marginal cost curve (MC1) in the diagram above might not be enough to change the profit maximising equilibrium.

The kinked demand curve model predicts periods of relative price stability under an oligopoly with businesses focusing on non-price competition as a means of reinforcing their market position and increasing their supernormal profits.

ALEVEL微观经济画图题建议

✪把图画大，大概A4纸的一半，这样可以让图表更加清晰

✪不要让解释和图挤在一起，可以空一行在下面开始解释，这样可以让卷面更加整齐

✪标记好每一条线代表的内容，平移的方向

✪标记好x轴、y轴分别代表的内容

本文对ALEVEL微观经济重要图表的介绍就到这里，希望能对你有帮助。

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