جستجوی مقالات مرتبط با کلیدواژه « gcct » در نشریات گروه « اقتصاد کشاورزی »

The aim of the present study was to investigate the possibility of aggregating and estimating the collective demand function for meat commodity groups (mutton, beef, poultry, canned fish, southern fish and northern fish) using Weak Separability methods, generalized composite commodity and the demand function of Iranian urban households. Necessary data and information were obtained from the annual statistics of expenses and income of Iranian households of the Statistics Organization for the period of 2005-2020. The results of income elasticity showed that two canned goods, fish and southern fish, are considered luxury for Iranian urban households. Northern fish with a self-price pull of -1.28 is most sensitive to price changes against other types of meat. Also, canned fish and southern fish are substituted based on the intersection of canned fish. According to the results of the Separability test for different types of meat, different types of meat can be divided into two groups of red and white meat.

Although prices of all commodities play a role in consumers’ decision-making process, the large number of individual commodities and prices creates problems in analyzing consumers’ choice. As a result, to the study consumer behavior, data aggregation is used quite often. To this end, different theories are proposed that justify consistent aggregation of commodities. The Generalized Composite Commodity Theorem (GCCT) and the testing procedure proposed by Lewbel is the original one that considers a necessary condition for consistent aggregation. Davis proposed aggregation testing approaches by resorting to the Bonferroni, Simes, Holm and Hochburg statistical methods for testing Generalized Composite Commodity Theorem in which the necessary and sufficient conditions are considered. This study is aiming to examine the possibility of aggregating meats, meat products, dairy products and eggs in a group named “Animal Proteins” and aggregating all grains in a “Vegetable Proteins” group, and to compare the aggregation results using Lewbel’s procedure and the approaches proposed by Davis using data over 1990-2012 period. Results show that based on the Lewbel’s method, all animal products except dough, curd and egg can consistently be aggregated in the Animal Protein group, and all grains including split peas, beans and lentils can be aggregated in the Vegetable Protein group. While based on Davis methods, all animal commodities without any exception can be placed in Animal Protein group and all grains are consistently aggregated in the Vegetable Protein group. These results indicate that the latter approach lets a wider range of commodities to be aggregated in a group. This implies that selecting an inappropriate aggregation method can lead to a bias in evaluating consumer behavior.