بررسی شرایط تجمیع و تحلیل تقاضای محصولات پروتئینی حیوانی

بررسی شرایط و عوامل موثر بر میزان تقاضا در کشور می‌تواند زمینه‌ساز ارائه راهکارهای لازم برای مهار بازار و یا سایر عوامل موثر بر مصرف محصولات پروتئینی حیوانی باشد. اما زمانی که بحث تقاضای مجموعه‌ای از خانوارها در سطح کلان کشور به میان کشیده می‌شود، موضوع تجمیع گروه کالاها اهمیت زیادی پیدا می‌کند. بنابراین، با توجه به اهمیت گروه‌بندی و تجمیع کالاهای مختلف، هدف مطالعه حاضر بررسی شرایط تجمیع محصولات پروتئینی حیوانی شامل گوشت قرمز، ماهی، مرغ، شیر و تخم مرغ با کاربرد روش‌های تفکیک‌پذیری ضعیف و کالای مرکب تعمیم‌یافته برای خانوارهای ایرانی در بازه زمانی 1400-1383 بود. نتایج آماره والد تعدیل‏‌شده مربوط به تفکیک‌پذیری ضعیف نشان داد که می‌توان گروه کالایی محصولات پروتئینی حیوانی یادشده را به سه گروه گوشت، شیر و تخم مرغ تفکیک کرد. نتایج محاسبه کشش‌ها نیز حاکی از آن بود که گوشت قرمز و ماهی برای خانوارهای ایرانی کالای تشریفاتی (لوکس) و مرغ، تخم مرغ و شیر کالای ضروری محسوب می‌شوند. با توجه به بالا بودن ضرایب کشش‌های متقاطع تقاضای گوشت قرمز و مرغ و همچنین، ماهی و گوشت قرمز، می‌توان انتظار داشت که با تغییر در قیمت گوشت قرمز، تقاضا برای گوشت مرغ و با تغییر در قیمت گوشت ماهی، تقاضا برای گوشت قرمز به‌گونه‌ای چشمگیر دچار تغییر شود. بنابراین، در اعمال مدیریت بهینه تقاضا و برنامه‌ریزی الگوی مصرف، استفاده از سیاست‌های قیمتی کالای جانشین می تواند کارآ باشد.

examining the conditions of aggregation and analyzing the demand for animal protein products

introduction: examining the behavior of consumers of various types of consumer goods in relation to the changes of different price and non-price factors and the effect of each of these factors on demand is considered as one of the important economic issues. estimating the demand function and calculating the elasticities of different groups of goods is one of the most important tools for investigating consumer behavior to know his preferences, and any policy and planning related to consumption requires analyzing the consumption pattern of households and knowing the position of each group of goods in the household budget. the large number of products and the lack of availability of sufficient information about consumer behavior make analyzing their behavior difficult. aggregation goods and use of composite commodity are considered as an effective solution to deal with issues such as the unavailability of detailed information of each item, heavy costs of data collection, the presence of missing observations, the occurrence of collinearity problems, and the limitation of degrees of freedom by researchers. but it is important that the grouping is done correctly and consistently, because incorrect grouping appears as a specification error in the demand system and affects the extent of estimated parameters and elasticities as well as the test of the assumptions of demand functions, the result of which is presenting a false picture of consumer behavior and creating deviations in policies. therefore, with respect to the importance of grouping and aggregation of different goods, this study aimed at investigating the conditions of aggregation of animal protein products including red meat, fish, chicken, milk and eggs using the methods of weak separability and generalized composite commodity for iranian households in the period of 2004-2021.materials and methods: the hypothesis of the research in the method of weak separability was that in the group of animal protein products, the products of three groups of meat (red meat, fish and chicken), milk and eggs could be identified as three composite groups and then, the above three groups considered as one composite group with the name of the group of animal protein products; also, the hypothesis that red meat, fish, chicken, milk and egg products could be specified as a composite group was tested using the generalized composite commodity method. in the present study, the quadratic almost ideal demand system (quaids) was used to investigate the weak separability.results and discussion: the results of the adjusted wald statistic related to weak separability showed that the product group of animal protein products (red meat, fish, chicken, milk and eggs) could be separated into three groups: meat, milk and eggs. in fact, the result of the test did not reject the assumption that consumers first would allocate a part of their expenses to the group of edible goods regardless of its type; then, the act of allocation between different types of groups of edible goods would be done based on their prices. the study results indicated that the red meat and fish were found to be luxury goods while chicken, eggs and milk were known as essential goods for iranian households.