消失的一亿女性
2010-08-31
此书既有趣，又能增加知识，特别我这种外行。里面有很多统计学的方法，和经济学研究有些许共通之处。有一处值得注意，对了解经济学的人来说。“令人惊讶的是，联合国的研究人员说大约有1亿女性从世界人口中消失。这是因为，亚洲的父母们更希望生男孩。”这例子在经济学领域被好多人研究过了，其中有几位大牛还在五大上发了文章。国内有不少人还津津乐道地把其搞个综述来回贴。简单的说，最新的有两篇较具影响力，Oster (2005) [1] 和 Qian (2008) [2]。前者(Emily Oster)用乙肝(Hepatitis B)解释，具体逻辑是医学研究表明患乙肝的妇女生男孩儿的概率比生女孩儿高。偷懒摘录下原文的摘要：
"This paper proposes an explanation for some of the observed over-representation of males: the hepatitis B virus. I present new evidence, consistent with an existing scientific literature, that carriers of the hepatitis B virus have offspring sex ratios around 1.50 boys for each girl. ... Hepatitis B is common in many Asian countries, especially China, where some 10 to 50% of the population is infected."
后者(Nancy Qian)主要用人为选择来解释这一现象。大体是说如果女孩儿能给家庭带来好的收益，选生女孩儿的家庭就多，反之也成立。再次偷懒：
"This paper uses exogenous increases in sex-specific agricultural income caused by post-Mao reforms in China to estimate the effects of total income and sex-specific income on sex-differential survival of children. Increasing female income, holding male income constant, improves survival rates for girls; while increasing male income, holding female income constant, worsens survival rates for girls."
还有一点，此书读起来很流畅，翻译的着实不错。
References
[1] Oster, Emily. 2005. "Hepatitis B and the Case of the Missing Women." The Journal of Political Economy. 113, pp. 1163 - 1216.
[2] Qian, Nancy. 2008. "Missing Women and the Price of Tea in China: The Effect of Sex-Specific Income on Sex Imbalance." The Quarterly Journal of Economics. 123, pp. 1251 - 1285.