公共事业管理专业英语

Public Good Demand

The demand or benefit from a public good is the sum of the willingness-to pay or benefit by consumers for each unit of the good．Each consumer shares the benefit from each unit of the good．This is unlike a private good，where each consumer gets a private benefit from each unit the consumer purchases without sharing the purchase or benefit with other consumers．Therefore，with a public good the benefit is the sum of the benefits from each consumer that receives a benefit from the unit of output．This is illustrated in the table below：

公共产品的需求和收益是消费者为每单位物品的支付意愿或收益的总和。每一个消费者享有每一单位物品的收益。这不像一个私人物品，在私人物品中，每一个消费者在不用与别人一起负担购买和分享收益的情况下，可以从每一单位的物品购买中得到得到每一单位的私人收益。所以在公共物品中，收益是每个从单位产出得到收益的每个消费者的收益的总和。这将会在下面表格陈述：

In the fictitious（虚构的）example in the table，the three scientists share a laboratory and are considering jointly purchasing several journal subscriptions．The journal subscriptions would be shared among the scientists．The table simplifies this decision by assuming that the journal subscriptions are similar and the benefit they receive from the first is the highest for all three scientists．The three scientists have a common second choice that they value less，a third choice，etc.，for the five journals they are considering jointly purchasing subscriptions to.

在表格里虚构的例子中，三个科学家共同享有一间实验室并考虑一起购买几种期刊订阅。期刊订阅将由三个科学家共同享有。通过假设期刊订阅是相似的而且他们从第一本得到的收益是最高的来用表格简化决策。这三个科学家有共同的第二种选择，但是他们对其评价要比第一本低一点，第三种选择所受到的评价又会再少一点，他们考虑共同购买的五本期刊以此类推。

Public goods should be jointly financed．The scientists may pool（合伙）their funds to purchase more journal subscriptions than each would individually．Assume for this example that a

personal subscription to each journal costs ＄１００．If the scientists purchase journals only for their private use，then George will subscribe to two journals while George would pay a total of ＄２００for two journal subscriptions．George’s consumer surplus would be ＄５０( the ＄２５０in benefit minus ＄２００cost )．

公共物品应该共同负担。科学家们可以合伙集资去买更多的期刊订阅，这样就会比一个人单独买的多。假设这个案例中一个人买一本期刊的话就要花费100美元。如果科学家只是购买期刊自己使用的话，乔治就会订阅两本，这就要花费掉他200美元。乔治的消费者剩余就会是50美元（250美元收益减去200美元成本）。

However，if the scientists pool their resources and order several subscriptions at＄１００each，they will purchase four journal subscriptions．The fourth subscription has a shared benefit of ＄１０４，while the fifth subscription has a shared benefit of ＄８７．The scientists would pay a total of ＄４００for the four subscriptions．Their consumer surplus would be ＄２５９( the ＄６５９in benefit minus ＄４００cost )．The journals are public goods，shared by the three scientists．The scientists’ public good demand and optimal number of subscriptions is shown in the figure below：

但是，如果科学家合伙集资以每本100美元的价格去订阅几种期刊，那么他们将订四本。第四本期刊有104美元的共同收益，而第五本只有87美元的共同收益。科学家将会支付400美元购买前四本期刊。他们的消费者剩余就会是259美元（659美元收益减去400美元成本）。期刊这样一来就是公共物品了，由这三个科学家享有。这三个科学家的公共物品需求和订阅的最佳数量在下图中展示：

in the figure，the public good demand curve is the vertical summation of the three scientists’demand curves．The price line at ＄１００crosses George’s demand curve at two subscriptions and the public good demand curve at four subscriptions．

在图中，公共物品的需求曲线是三个科学家需求曲线的垂直相加之和。100美元的价格水平线将乔治的需求曲线的订阅数为2本那里穿过，而在公共物品需求曲线的订阅数为4本那里穿过。