“紅燈區”里的經濟學

2011年09月09日 06:52 AM
“紅燈區”里的經濟學
Green lights for red-light districts
作者：英國《金融時報》專欄作家 蒂姆•哈福德

The sex workers of Tampa, Florida, and Charlotte, North Carolina, can get ready for a spike in business at the end of next summer: the Republican and Democratic National Conventions, respectively, are coming to town. In the last electoral cycle, the political jamborees were held in Denver and Minneapolis – and there seems to have been a coincidental surge in the local market for sex.
佛羅里達州坦帕市和北卡羅來納州夏洛特市的性工作者可以為明年夏末業務量飆升做好準備了：共和黨和民主黨全國大會將分別在這兩個城市召開。在上一次選舉周期中，這兩場政治盛會分別在丹佛和明尼阿波利斯召開，巧合的是，當地性服務市場似乎同時出現了大幅增長。


The economists Scott Cunningham and Todd Kendall discovered this by examining advertisements in the “adult services” section on Craigslist, the online ad service. (Craigslist has since closed down this section.)
這是經濟學家斯科特•坎寧安(Scott Cunningham)和托德•肯達爾(Todd Kendall)對在線廣告服務Craigslist的“成人服務”版廣告研究後的發現。（此後，Craigslist關閉了這個版面。）

Using postings in Seattle and Philadelphia as a control group – these cities did not have almost 50,000 visitors descending on them for a few days – the economists estimated that advertisements selling sexual services increased by 29-44 per cent in Minneapolis during the Republican visit and 47-77 per cent in Denver when the Democrats arrived. I’m not going to make jokes about oversexed politicians, largely because the majority of visitors appear to have been journalists.
將西雅圖和費城張貼的廣告作為對照組——這些城市不會在幾天內突然增加近5萬訪客——這兩位經濟學家估算出，在共和黨開會期間，明尼阿波利斯性服務廣告增加了29%至44%，在民主黨開會期間，丹佛的性服務廣告增加了47%至77%。我並不打算拿那些性欲過度的政治家開玩笑，這主要是因為大多數訪客似乎是記者。

Perhaps we should not be surprised that when a large number of people drop into town, many of them men, local sex workers see an opportunity to do business. Tourists worry less about being spotted by a neighbour or a colleague. And to the extent that some men may be weighing up the relative attractions of paying for sex versus looking for a wife or girlfriend, being in a city far from home makes looking for a girlfriend relatively less tempting.
當大批訪客來到一個城市，其中很多為男性時，當地性工作者會將其視為一個商機，或許我們不應對此感到意外。游客不會那麽擔心被鄰居或同事發現。有些男人可能會衡量出錢嫖妓和找老婆或找女友哪個更有吸引力，從這點來說，身處一個遠離家門的城市時，找女友相對而言就不那麽吸引人了。

It may seem alarmingly cold to view men as weighing up the costs and the benefits of finding a wife versus hiring a prostitute – and just as stark to view women as making the same decision in reverse – but the idea is not mine. Almost a decade ago, two economists, Lena Edlund of Columbia University and Evelyn Korn of the University of Marburg, published an article, “A Theory of Prostitution”, which modelled exactly these decisions. One of their purposes was to explain why sex workers can earn so much money. The abstract begins with a puzzle: “Prostitution is low-skill, labour intensive, female and well paid.” The economists suggested a “marriage market explanation” as the reason why. If marriage can provide women with an important source of income, “it follows that prostitution must pay better than other jobs to compensate for the opportunity cost of forgone marriage market earnings”.
認為男人會衡量找老婆和招妓的成本和好處，似乎顯得太過沒有有人情味，而認為女人反過來也在做著同樣選擇的觀點也同樣冷酷，但這並非我的看法。近10年前，兩位經濟學家——哥倫比亞大學(Columbia University)的莉娜•埃德倫德(Lena Edlund)和馬爾堡大學(University of Marburg)的伊芙琳•科恩(Evelyn Korn)發表了一篇名為《賣淫理論》(A Theory of Prostitution)的文章，以完全相同的抉擇為研究模型。他們的目的之一是解釋性工作者為何收入如此之高。論文摘要的開頭便是一個讓人費解的謎題：“賣淫工作技術含量低、屬於勞動力密集型產業，從業人員多為女性、但薪酬豐厚。”這兩位經濟學家提出“婚姻市場說”對原因進行解釋。如果婚姻可以為女性提供一種重要的收入來源，“那麽合乎邏輯的推論就是，妓女必須獲得比其它工作更高的收入，以彌補放棄婚姻市場收入的機會成本”。

When men are in transit, and so less likely to be interested in marriage, it should be no surprise that sex takes off in the spot market. In their study, Edlund and Korn cited mining camps, military bases, 19th-century American frontier towns and sex industries driven by a surplus of men in African cities. In short, there is nothing special about American political conventions. What might be more surprising is the idea that some women dip into the sex industry very occasionally. In an unpublished paper, Steve Levitt and Sudhir Venkatesh gather data on street prostitutes in Chicago, a different segment of the market from those advertising on Craigslist. Levitt and Venkatesh find that on the Fourth of July holiday demand rose by 60 per cent and prices by 30 per cent. This price increase proved sufficient to tempt some women into sex work for one day of the year.
男人出門在外時，不太可能對婚姻感興趣，因此當地市場上的性服務會很受歡迎，也就不足為奇了。在埃德倫德和科恩的研究中，她們舉出了採礦場、軍事基地、19世紀美國邊境城鎮和在非洲城市性行業受男性過剩推動等例子作為證據。簡而言之，美國政治會議沒有什麽特殊之處。或許更令人意外的一個觀點是，一些女性只會非常偶過性地加入性服務行業。在一篇未發表的論文中，史蒂文•萊維特(Steven Levitt)和素德赫•文卡特斯赫(Sudhir Venkatesh)收集了有關芝加哥街頭妓女的數據，這是與Craigslist上的那些廣告截然不同的細分市場。萊維特和文卡特斯赫發現，在7月4日國慶假期那天，性服務需求增加60%，價格也上漲30%。事實證明，這一價格漲幅足以吸引一些女性在一年中有那麽一天加入到性工作者的行列中來。

All this is fascinating from an economic point of view: the market for sex is a market like any other. But some of it is also worrying. Both the mobile buyers of sex and the workers who sell it have long been identified as vectors for sexually transmitted infections. Levitt and Venkatesh find that in the street transactions they analyse, condoms are rarely used. Perhaps those Craigslist advertisements Cunningham and Kendall found were facilitating safer sexual encounters. Let us hope so.
從經濟角度來看，所有這一切都頗為有趣：性市場與其它任何市場都一樣。但其中也存在一些令人擔憂的問題。長期以來，購買性服務的流動人口以及經常出售性服務的人一直被認為是性傳染疾病的病菌攜帶者。萊維特和文卡特斯赫發現，在他們分析的街頭交易中，很少有人使用避孕套。或許，坎寧安和肯達爾在Craigslist上發現的那些廣告是在促進更安全的性生活。但願如此吧。

Tim Harford’s new book is ‘Adapt: Why Success Always Starts With Failure’ (Little, Brown)
蒂姆•哈福德的新書名為《適者生存：為何失敗是成功之母》(Adapt: Why Success Always Starts With Failure)，由利特爾-布朗公司(Little, Brown)出版

譯者/何黎