劳动剩余条件下的供给不足与工资上涨——基于家庭分工的视角

基于贝克尔家庭经济学和时间配置理论可以证明，劳动剩余条件下的劳动供给并不是无限的。受制于家庭分工的约束，供给曲线呈特殊的阶梯形态：随劳动供给的增加，农业劳动力的保留工资不断提高，且幅度不断扩大。劳动供给对工资的反应是非连续的：只有当工资上升到新的保留工资水平时，劳动供给才会增加；否则，工资上涨并不能带来供给增长。与这种特殊的供给形态相对应，工资上涨的主要动力从农业收入转向工业劳动需求。内蒙、甘肃两省1，500个农户的调查数据证明了上述判断。当劳动需求扩张时，由于工资的微调不能带动供给的微调，劳动力市场将长期难以出清。这提醒我们，当前农民工工资上涨与用工短缺并存现象很可能源于劳动剩余条件下的供给不足，并不必然意味着剩余劳动力枯竭，不能作为刘易斯拐点到来的证据。

Insufficient Labor Supply and Wage Rises under Conditions of Labor Surplus:From the Perspective of the Intra-household Division of Labo

On the basis of Becker’s family economics and the theory of time allocation, it can be shown that labor supply under labor surplus conditions is not unlimited. Under the constraints of intra-household labor division, the supply curve takes on a special staircase form:as labor supply increases, the reservation wage of rural labor rises by an ever larger margin. The response of labor supply to wages is discontinuous. Labor supply will increase only when wages reach the new level of the reservation wage; otherwise, wage increases do not lead to an increase in labor supply. Corresponding to this special form of supply, the major driving force behind wage increases becomes industrial labor demand rather than agricultural income. The data from a survey of about 1,500 rural households in Gansu and Inner Mongolia bear out the above proposition. When labor demand rises, slight wage adjustments will not bring a corresponding increase in labor supply and labor market clearing will not occur for a long time. This reminds us that the present coexistence of a shortage of labor with wage rises for migrant workers may well derive from insufficient labor supply under labor surplus conditions. It does not necessarily imply the exhaustion of the labor surplus and cannot serve to prove the arrival of the Lewis turning point.