【专题】宏观经济学：unemploymentrate
　　【问题】
　　holding the working-agepopulation constant, if the labor force participation rate declines while thenumber of people employed remains unchanged, the unemployment rate is mostlikely to
　　A. increase
　　B. decrease
　　C. remain unchanged.
　　答案是B。可是unemployment rate不是等于no. of unemployed/laborforce么？ 题干里说labor force减小了，其他remainunchanged,那unemployment rate 不是应该increase么？
　　【专家解答】
　　labor force participation rate=（unemployed +employed）/working-age population
　　题目中说“the number of peopleemployed remains unchanged”，” holding the working-agepopulation constant”，也就是就业人数不变，工作年龄人口数量不变，而劳动参与率下降，所以，laborforce数量减少，unemployed数量减少。
　　unemployment rate=unemployed/labor force=unemployed/（unemployed+employed）=1/（1+ employed/unemployed）
　　由于employed不变，unemployed减少，因此employed/ unemployed变大，进而unemployment rate分母项变大，所以unemployment rate变小。