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。

This is an example of a special or corporate library．In this small corporate library there are three scientists who have a public good demand for journal subscriptions．In any library，there are patrons（顾客）who have a public good demand for access（to cooks，journals，databases，reference services，and other materials and services．The use of library services reflects the demand for these services by patrons．Even if patrons are not charged a price for access，they have an opportunity cost of time spent traveling to and using the services．The public good demand curve for library services can be constructed by summing the value of each patron’s demand．In a corporate library there is also the benefit to the corporation of the scientists’ access to the library services．New products and services developed by scientists increase the profitability （营利能力）of the corporation．The increase in corporate profit，over and abovewhat the scientists view as their demand for the library，is also part of the public good demand for the corporate library services．

这是一个特殊或共用的图书馆例子。在这一间小小的共用图书馆有三个科学家，他们都有对期刊订阅的公共物品需求。在任何图书馆，都有对烹饪、期刊、数据库、参考咨询服务和其他资料有需求的顾客。图书馆服务的使用体现在顾客对这些服务的需求上。即使顾客没有为这些使用缴费，但他们也可能存在用在路途上和使用这些服务的时间成本。图书馆服务的公共物品需求曲线可以通过对每个顾客的需求评价叠加来构建。在一个共用的图书馆也存在科学家共同使用图书馆服务的收益。科学家开发的新产品和服务可以增加共同的营利能力。共用营利的增加超过了科学家们认为对图书馆的需求评价，也是共用图书馆服务的公共物品需求的一部分。

Estimating demand for public goods is difficult．When consumers are charged for access，we can use data on the amount they purchase to estimate their demand．For example，the number of newspapers，copies of a software program，cell phone minutes of access，or movies tickets sold can be used to estimate demand．However，when consumers are not charged for access，economists must be creative in finding metrics to use for demand analysis．The use of special，public，school，or research libraries along with the opportunity cost of this use can be helpful in determining demand for these public goods．Proxies for use include circulation，reference

questions asked，interlibrary loan items requested，library web page hits，and number of library visitors．

对公共物品的评估是困难的。当对消费者收费时，我们可以通过他们购买数量的数据来评估他们的需求。举个例子，新闻报纸、软件程序的副本、电话使用分钟数或者是卖出电影票的数量可以被用来评估需求。但是，当消费者没有为使用付费时，经济学家在寻找用来做需求分析的度量标准就必须要有创造力。特殊的、公共的、学校的或者是调查研究的图书馆的使用连同使用的机会成本都会对决定这些公共物品需求有帮助。使用代理包括循环、要问的参考问题,要求的图书馆馆际的贷款项目,图书馆网页页面点击量和图书馆游客的数量。

Demand for public goods is also estimated by asking patrons or citizens to quantify the benefit they receive from the goods．For example，surveys of library patrons ask which services patrons would like increased or decreased．Surveys of citizens ask about the financing of community services．Economists have found that it can be difficult to calculate the demand for public goods from these surveys because citizens have an incentive to misrepresent the benefit they receive from services if they feel it may increase these services or increase their taxes．Finally，many public goods produced by governments are influenced by election results．Public school and public library budgets are voted on by local residents．The residents express their demand for these services by voting for or against the proposed level of spending．Although these methods of measuring the demand for public goods may be imprecise，it is important to try to assess the demand and cost of a public good to determine the efficient level of output．

公共物品的需求也可以通过叫顾客或者市民来量化他们使用这些物品的收益来进行评估。比如，图书馆顾客的调查可以询问顾客希望增加或减少哪种服务。市民的调查可以询问社区服务的筹措资金的问题。经济学家已经发现很难从调查中计算公共物品的需求，因为如果市民觉得它可能增加这些服务或提高他们的税收，他们就会倾向歪曲他们从这些服务中得到的收益。最后，由政府生产的许多公共产品会受到选举结果的影响。公立学校和公共图书馆由当地居民投票决定。居民通过投票支持或否决提出的开支来表达他们自己的需求。尽管这些衡

量公共产品需求的方法可能不准确，但它对尝试了解一种公共产品的需求和成本从而决定有效率的产出显得就很重要。