چکیده:
Given the importance of food items in household baskets, this article systematically examines the food expenditures of urban households during the period 1983–1984 (1362–1379 SH). In this system, the share of food expenditures is calculated as a function of the price of that commodity, the prices of other food commodities, and the real income allocated to food. For model design, the food commodity group has been divided into 8 groups: rice, flour and its products, red meat, white meat, milk and its products, vitamins, animal oil, vegetable oil, and other food products. In this study, using economic variables based on microeconomic theoretical principles, we have also estimated the cost share and explained price and income elasticities. The data used are applied in a combined manner, meaning a combination of cross-sectional and time-series data, and parameters have been estimated using seemingly unrelated regression techniques. Additionally, to test the stationarity of the model variables, we utilized the Augmented Dickey-Fuller (ADF) test. Subsequently, homogeneity and symmetry tests were considered, and the error correction method was used for model specification. Since households make decisions on food expenditures in a two-stage process, we have used the two-stage budgeting technique to estimate food expenditures, where the fundamental assumption in this regard is weak separability. The estimation results show that the income elasticity of food commodities is less than unity, while the income elasticity of non-food commodities is greater than unity. Furthermore, in the food commodity group, theown-price elasticities have a positive sign, and the income elasticity for rice, flour and its products, milk and its products, vegetable oil, and vitamins is less than unity, whereas in commodities such as red meat, white meat, animal oil, and other food products, it is greater than unity.
خلاصه ماشینی:
Since the goal is to estimate the system of demand equations in the food group, we will examine the following statistics: 1- Rice, flour and its products 2- Red meat 3- White meat 4- Milk and its products 5- Vegetable oil 6 – Animal oil 7 – Vitamins 8 – Other edible products Table number (1) considers the average food and non-food expenditures incurred by an urban household at current prices.
The specification of model number (17) in this study has been carried out as follows: (19) According to table number (6), the estimation results across all income classes indicate the necessity of food commodities relative to other goods in the household budget, and as mentioned in the data analysis section, food commodities hold the status of necessary goods in the consumption basket of households relative to their other consumer goods.
The column [coefficient of the logarithm of real income (estimations)] indicates whether goods are necessary or luxury; because according to formula number (10), if it is, we will witness luxury (necessary) goods; therefore, before determining the actual size of income elasticities, it can be stated that meat products (red, white), animal oil, and food products, due to being positive, hold the status of luxury goods relative to other goods present in the food basket of urban consumers.
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