经济学人下载: 奥运经济学 令人沮丧的百米冲刺

Finance and Economics；Olympionomics;The dismal dash;Which economist will win themedal-prediction gold?
财经；奥运经济学；令人沮丧的百米冲刺；哪位经济学家能够成为“奖牌预测大赛”的冠军呢？

Athletic prowess is not all that is being tested at this year's Olympic games. There will also be teams of econometricians battling it out to predict how many medals will be won by the host nation.
今年的伦敦奥运会比的已经不仅仅是运动员高超的技艺。还有计量经济学家们组成的各支代表队将在“场上”进行激烈地角逐，争夺“预测东道主英国奖牌数量”大赛的冠军。

Over the years economists have deployed all sorts of mental gymnastics in their search for a model that can reliably forecast Olympic winners. Initial expectations that medal tallies would be closely correlated with the population and per-capita wealth of a country were soon dashed. The models leapt over the hurdle of statistical significance only when a third variable was added—how many medals the country won last time—but this did not add much by way of explanation.
在过去的几年里，经济学家们使出浑身解数，想要找到一种能够预测奥运会奖牌数量的可靠模型。一开始，他们认为一个国家在奥运会上所获奖牌的数量可能和这个国家的人口以及人均收入有紧密联系。但这样的想法很快就被排除了。而那些可以不需要考虑显著性差异的预测模型只有当加入第三个变量（即这个国家在上一届奥运会中获得了多少奖牌）时才能够成立。但换句话说，这样的变量也起不了太大的作用。

Apart from the persistence of good (or bad) performance from one Olympiadto the next, the dismal scientists hopped, skipped and jumped to two otherstatistically significant results. First, there was a“Soviet effect”, whereby the planned economies of the former communist bloc tended to outperform, presumably due to forcing talented youngsters to specialise and pumping them full of steroids . This effect began to fall with the Berlin Wall.
除了考虑到运动员在前后两届奥运会中能够持续发挥良好（或者差劲），这些“神情沮丧”的科学家们煞费苦心地找到了其他两种具有显著性差异的结果。首先，有这样一种“前苏联效应”，而且曾经以计划经济体制为指导的社会主义阵营国家正是凭借着这样的一种效应才在奥运赛场上表现得异常出色。有人猜测，这些社会主义国家强迫那些富有才华的年轻运动员们专攻竞技比赛，并给他们大量服用类固醇药物。但是这样的效应随着柏林墙的倒塌也开始日渐步入下风。

Second, the host nation tends to win more medals than it does at any other time. Why it does so is unclear, as is the exact size of the “host effect”—which is why, for economists, predicting how many medals Britain will bag is the equivalent of winning the 100-metre dash. Emily Williams, the torchbearer for the Tuck School of Business team that won the medal-forecasting gold last time with 95% accuracy, tips Britain's athletes to win 62 medals (25 of them gold), up from 47 four years earlier in Beijing. That would be a record haul for Britain, and place it fourth overall, behind America (103), China (94,down from 100 when it hosted), and Russia (67).
其次，东道主国家似乎比以往任何时候都能够赢得更多的奖牌。不过其中的原因并不清楚，这就好比经济学家们并不知道“主场效应”具体能发挥多大的作用一样。因此，对他们来说，预测出英国今年能够包揽奖牌的数量就相当于赢得了这项百米冲刺的冠军一样。来自达特茅斯塔克商学院的艾米莉·威廉姆斯（Emily Williams），在北京奥运会召开时，带领她的团队以95%的准确率赢得了这块“奖牌数量预测大赛”的金牌。她指出，这次英国以四年前的47块为基础，总共将赢得62枚奖牌（其中包括25枚金牌）。而这样的数字也将使英国创下纪录，进入奖牌排行榜第四位，紧随美国（103枚），中国（94枚，比北京奥运会时的100枚有所下降）和俄罗斯（67枚）其后。

By contrast, PricewaterhouseCoopers thinks Britain will win 54 medals, and Daniel Johnson of Colorado College, another veteran forecaster, actually thinks Britain will win fewer medals at home than it did four years ago in Beijing(down by two to 45). The new comer to the field is Kevin Daly, an economist at Goldman Sachs, who calculates that on average the host nation of an Olympics wins 54% more medals than usual. Taking Britain's 47 last time as “usual”, that would translate into a whopping 72 medals in London. We shall soon find out which, if any, of these dismal scientists is on the right track.
与之相反的是，普华永道的经济学家们认为英国今年将赢得54块奖牌；同时，来自科罗拉多学院的老牌预测行家丹尼尔·强生（Daniel Johnson）实际上也认为英国今年将比四年前拿得奖牌少一些（比四年前减少两枚，即45枚奖牌）。不过，来自高盛（Goldman Sachs）的新手，经济学家凯文·戴利（Kevin Daly）计算出：一般情况下，奥运会的东道主国家比往常获得的奖牌数量要多54%。就拿四年前的“47”块奖牌作为往常量，而经过运算后就得出今年伦敦奥运会英国将获得惊人的72枚奖牌。当然，不久我们就能知道这些经济学家中谁预测的结果最准（如果有人预测准确的话）。