“价格弹性”考点讲解，清晰的解题思路不怕你学不会！

“价格弹性”考点讲解，清晰的解题思路不怕你学不会！

价格弹性（price elasticity）是A-level 经济学里比较重要和难懂的部分，既因为它本身的定义晦涩难懂，距离现实比较远；同时也因为考察价格弹性这个知识点的方式很灵活，包括图像和计算。

但是一旦完全掌握了价格弹性的定义和公式，在回答三选一的AS阶段的Section B的时候，不失为一个好的选择。

下面我们通过真题看看关于价格弹性问题的问法和解题思路（CIE考试局）

(a)Explain two factors that are likely to make the supply of a product relatively price inelastic. [8]

(b)Discuss how governments might attempt to make the supply of an essential good more responsive to a change in its price and assess the likely effectiveness of such attempts. [12]

Part.1审题分析

首先是审题的部分，我们先来看看（a）部分。

关键词是：two factors 和 price elasticity of supply还有relatively。

翻译过来就是例举两个能让供应价格弹性相对降低的因素，我们要从knowledge and understanding和application两个角度来回答这个部分。

对于（b）部分来说，关键词是：more responsive和effectiveness。

翻译过来就是，讨论一下政府怎么能增加某种商品的价格弹性（more responsive）和此类政府干预手段的有效性。我们在回答此类问题的时候要注意analyse政府干预方法和evaluate该方法的有效性。

Part.2逻辑梳理

其次，我们需要针对题目，对答案的内容和逻辑关系进行梳理。

我们先看（a）部分,从knowledge and understanding的角度来说，我们应该回答供应价格弹性的定义和相对价格非弹性（relatively price inelastic）。

从application的角度来说，我们要在这里例举两个能导致供应价格弹性相对降低的因素。比如：时间跨度（short run  long run）；替代品的数量；生产资料的获取难度和供应商的数量等等。

然后我们再来看看（b）部分，某种商品的supply变得more responsive to its price 的意思就是该商品的供应价格弹性增加。

所以我们就应该考虑，什么样的政府干预手段可以让某个商品的市场供应量，在价格增加的时候大幅度增加。我们应该提出两个干预方法和相应的可能存在问题。

Part.3解答

重点

（a）Elasticity of supply means the responsiveness of quantity supplied to change in price, which can be measured by price elasticity of supply. The supply of one good being relatively price inelastic means there is a less than proportionate response in quantity supplied to a change inprice. （供应价格弹性和相对非弹性的定义）

Factors that are likely to make supply price inelastic are difficulty of entrance to the market is high（进入市场很困难） and the time it takes for the input to vary is very long（生产资料投入的改变需要很长时间）.

（b）Government might attempt to provide related labor training program to the price elasticity of supply of a product.（政府可以通过提供劳工提升项目来提高劳工的素质水平，从而增加供应价格弹性）

If an enterprise is able to hire more labor required to increase production as response to increase of the price of the product, the price elasticity of the supply are likely to be high.（如果公司可以在短时间招到合适的工人来增加供应产量的话，供应价格弹性就会比较高）

Government might provide buffer stock scheme to the availability of stocks during shortages.（政府也可以通过库存缓冲法来增加弹性）government releases the stock to the market as response to the increase of the price, which makes the price elasticity of supply higher.（政府通过在价格升高的时候向市场释放存量来提高产品供应弹性）

The first method might cost too much for free labour training programme as a public good, which would create dead weight loss.The second method might also cost too much especially if the storage cost to keep the product consumable very high.