UNDERCOVER ECONOMIST: FOR BETTER OR WORTH
可乐价格为何60年不变？

作者：英国《金融时报》专栏作家蒂姆•哈福德(Tim Harford)

2007年5月15日 星期二

The price of the first serving of Coca-Cola was five cents in 1886, which is about a dollar (50p) in today's money. Coke no longer sells for a nickel, and that is not terribly surprising. What is surprising is that it took more than 60 years for the price of Coca-Cola to change.
1886年，一罐可口可乐(Coca-Cola)的价格是5美分，大约相当于今天的1美元（50便士）。如今的可乐售价不再是5美分了，而这并不特别令人惊诧。真正令人惊诧的是，可口可乐的价格用了60多年的时间才发生变化。

Economists call this nominal price rigidity. My salary is not tweaked each month to reflect the latest inflation figures, and neither is yours. Restaurants do not reprint their menus, nor wholesale companies their catalogues, if the cost of their inputs changes by a penny.
经济学家将这称为名义价格刚性。我的工资并非每个月进行调整，以反映最新的通货膨胀数据；你的工资也一样。如果原材料成本发生一分钱的变化，餐馆不会重新印制菜单，批发公司也不会修改商品目录。

That might be a problem. Prices keep the economy running smoothly by adjusting to reflect demand and the underlying costs of production. If prices don't adjust smoothly for any reason then the economic consequences could be serious. If wages can't fall in a recession then people will lose their jobs instead. If prices can't fall when demand does, sales will collapse with much the same effect.
这可能是个问题。价格之所以能够保持经济平稳运行，是因为它会做出调整，以反映需求和潜在的生产成本。如果价格因为某种原因而没有进行平稳调整，那就可能造成非常严重的经济后果。经济衰退时，如果工资未能下降，那么人们将会失业。需求下降时，如果价格不能下跌，那么销售将崩溃，结果还是一样。

Coke was clearly an exceptional example of rigid prices. Daniel Levy and Andrew Young, the economists who analysed the case, report that Coke's price stayed at five cents a serving while the price of other products bounced all over the place. The price of sugar tripled after the first world war before falling back somewhat; over the six decades, the price of coffee went up eightfold. Coke itself was taxed first as a medicine, then as a soft drink, and survived sugar rationing. All the while the price stayed at a nickel.
可乐显然是价格刚性的一个突出案例。经济学家丹尼尔•利维(Daniel Levy)和安德鲁•杨(Andrew Young)对此进行了分析。他们撰写报告称，当其它商品价格都在上涨时，可乐价格一直保持每罐5美分。糖价在第一次世界大战后上涨了两倍，然后略有回落；在60年期间里，咖啡价格上涨7倍。可乐本身最早作为一种药品纳税，然后作为软饮料纳税，还承受了糖配给供应。但自始至终，它的价格都保持在5美分。

Part of Coke's problem was the cost of replacing vending machines that accepted only nickels - and the fact that the alternative, dimes, represented a 100 per cent price hike. (The boss of Coca-Cola wrote to his friend President Eisenhower in 1953 to suggest, in all seriousness, a 7.5 cent coin.)
可乐的价格问题，部分在于更换自动售货机的成本（这些机器只接受5分镍币），以及若改为接受一角硬币，意味着价格将上涨100%。（可口可乐的老板曾于1953年写信给他的朋友、美国总统艾森豪威尔，非常严肃地建议使用7.5美分的硬币。）

Most companies don't wait so long to change prices if they need to. Researchers have tended to conclude that many prices change every year or so, and often sooner. Levy and some colleagues looked at supermarket pricing in the mid-1990s and found, based on detailed accounting data, that to change the price of a single type of product in a typical supermarket cost 52 cents in printing, labour and errors. The total of all such changes was about $100,000 per store per year - still less than one per cent of revenue.
对于多数公司而言，如果有必要改变价格，它们一般不会等太久。研究者往往得出结论称，许多商品价格变化的周期是一年左右，往往还会更快一些。利维和一些同事考查了上世纪90年代中期的超市定价，在详细研究了会计数据后发现，一家典型的超市要改变某类商品的价格，需要在印刷、劳动力和误差方面花费52美分的成本。一家商店每年进行价格变化的总成本为10万美元——仍不足其营业收入的1%。

Technology makes it ever easier to change prices using bar codes, websites, and laser-printed menus. Amazon always seems to be changing book prices. Coke vending machines now take very little effort to reprogram. So should we conclude that ”menu costs” no longer matter?
运用条形码、网站和激光打印的菜单，科技使得调价变得更容易。亚马逊(Amazon)似乎总是在改变图书的价格。如今，改编可乐售货机的程序几乎不用费什么力气。因此，我们是否应该得出“菜单成本”(menu costs)不再重要的结论呢？

That would be too optimistic. Economists have long argued that even small ”menu costs” could cause large economic distortions, because when companies are pondering whether to pay those costs, they don't consider the social benefits of a more accurate price, only their own profits.
这一看法可能过于乐观。经济学家长期以来一直主张，即便是微小的“菜单成本”也可能导致严重的经济扭曲，原因是当企业考虑是否支付这些成本时，它们想到的只是自己的利润，而不会考虑提高价格准确性所带来的社会利益。

A prize-winning paper from Carlos Carvalho recently showed that it does not even help if many prices adjust quickly, because those that change slowly will distort the rest. Amazon may be able to adjust its prices easily to reflect its costs, but that is little use if those costs are distorted by slow adjustments from, say, the bookbinders or the freight handlers.
卡洛斯•卡瓦略(Carlos Carvalho)最近获奖的一篇论文表明，即便是许多商品价格进行了迅速调整，结果也无济于事，因为变动缓慢的价格将会扭曲其它价格。亚马逊或许能够轻松调整图书价格，以反映其成本，但如果图书装订商或货运商的价格调整缓慢，导致这些成本扭曲，那么，亚马逊的做法就没什么作用。

Coca-Cola's experience reflected exactly that: long before the introduction of vending machines, they had signed a perpetual fixed-price contract to supply their bottlers, at a time of very low inflation.
可口可乐的案例反映的正是这种情况：早在引入售货机之前很久，该公司就在通胀非常低的时候签署了长期的固定价格合同，向罐装商供应可乐。

I drank a 500ml bottle of Coke while writing this article, and it cost me 85p ($1.70) from the corner shop. I'd rather have paid a nickel, but price changes are important. Perhaps I shouldn't be too ungrateful.
在撰写本文时，我喝掉了一瓶500毫升的可乐。这是我从街角的商店以85便士（合1.70美元）的价格买的。我宁愿付的是5美分，但价格变化非常重要。或许我不应该太不知感激。