An Econometric Analysis of the Outsourcing of Meals and Household Activities

在家做饭的食品支出占总食品支出的比例正在下降，而其余的如方便食品（熟食、快餐等）和外出就餐的支出比例正在增加。这种家庭食品消费的趋势被称为“用餐外包”，它展示了用方便食品和外出就餐代替自制饭菜的过程。因此，餐饮外包可以被认为是市场商品和服务的替代活动，并且涉及到用于家务劳动的时间的变化。本研究的目的在于厘清餐饮外包与家庭活动之间的关系。工资率和家庭规模的变化是重要的相关因素。研究框架和结果如下：用统计学方法对上述替代进行了实证研究。根据家庭需求模型推导出家庭自制食品的需求函数，并提出了以下两个假设：根据工资率的上升，方便食品和外出就餐取代了自制饭菜，因为家务劳动的机会成本上升（假设I）；根据家庭规模的缩小，方便食品和外出就餐取代了自制饭菜，因为家庭生产效率下降，人均家庭烹饪的机会成本上升（假设II）。作为估计的结果，假设是支持的。这可以解释为，事实上，作为外包的饭菜是一个非常经济的行为，为家庭节省了昂贵的自制饭菜，方便食品和外出就餐取代了自制饭菜，因为自制饭菜的机会成本已经变得很高的工资率的上升，因为家庭规模的缩小。

The expenditure ratio of foodstuffs for homemade meals to total food expenses is decreasing, though the rest such the proportion of expenditure for convenience foods (cooked foods, fast foods, and so on) and eating out is increasing. This trend of food consumption by households is called outsourcing of meals, and it shows the process, which substitutes homemade meals with convenience foods and eating out. Therefore, the outsourcing of meals can be considered to be replacement activities for the market goods and services, and involves changes in time used for housework.The purpose of this study is to clarify the relation between outsourcing of meals and household activities. Changes in wage rate and family size take up as important related factors.The framework and results are as follows ;1. The substitution mentioned above is investigated empirically by the statistics.2. The demand function of foodstuffs for homemade meals is derived from the household demand model and the following two hypotheses are presented ; According to a rise in the wage rate, convenience foods and eating out are substituted for homemade meals because the opportunity cost of housework goes up (hypothesis I), According to a reduction in the family size, convenience foods and eating out are substituted for homemade meals because the efficiency of domestic production falls and the opportunity cost of domestic cooking per person goes up (hypothesis II).3. As a result of estimation, the hypotheses are supported. It can be explained that the fact as outsourcing of meals is a very economical behavior by households for which saves costly homemade meals, and convenience foods and eating out replace homemade meals since the opportunity cost of homemade meal preparation has become high by a rise in the wage rate and because of the shrinking size of the family.