"口味无争辩"? 高低收入阶层膳食健康上的不平等及其分解

我国高低收入阶层间存在着严重的膳食健康上的不平等现象, 在讨论其背后的机制时，鲜有文献涉及到口味因素．传统理念认为口味差异天生给定, 无需争辩; Becker 开创性地认为可以用经济学工具争辩口味问题．通过采用中国家庭追踪调查 (CFPS) 2010年 - 2014 年三期面板数据进行分析, 加入个体固定效应的再中心化影响函数回归, 消除了 "不可争辩的口味"; 在此基础上进行无条件分位数分解, 将相同特征条件下系数不同导致的不平等定义为“可争辩的口味”效应．结果显示: 在包含收入阶层流动的情况下，"可争辩的口味" 和社会经济地位分别可以解释膳食健康不平等的 54.3% 和 44.5% ; 在不包含收入阶层流动的情况下, 二者分别可以解释 37.1% 和 62.3% , 人口学特征、个体健康、供给因素的作用很小．结论表明, 收入政策只能起到部分作用, 政策制定者需要重视对口味的教育引导．这在 "健康中国 2030" 背景下, 对于促进全民健康有着重要启示．

There is a serious inequality of dietary health between the high-income and low-income classes in China, which is generally considered an important issue facing this country. When inferring potential causes of this inequality, extant literature usually neglect the effect of an individual’s taste. Applying the panel structure of CFPS 2010－2014 data, recentered influence function (RIF) method is first employed to eliminate individuals' "inborn taste" through controlling for individual fixed effect, then unconditional quantile decomposition is conducted to further separate the effects due to ( 1) individuals' different characteristics (e.g. socioeconomic and demographic factors) and ( 2) individuals' different marginal utility (i.e. coefficients) of inequality as a result of differences in coefficients with the same characteristics, which is defined as the effect of
"alterable taste". It is found that with the presence of income class mobility, :alterable taste" and socioeconomic status can explain 54.3% and 44.5% of the dietary health inequality, respectively; In the absence of income class mobility, the two different tastes can explain 37.1% and 62.3% respectively. These results imply that government’s income policy can only partially influence individuals' dietary health. The policy makers are suggested to invest more in taste education and help individuals to foster a healthy and balanced diet.