با همکاری انجمن اقتصاد کشاورزی ایران
نوع مقاله : مقالات پژوهشی
نویسندگان
1 گروه اقتصاد کشاورزی ، دانشگاه تهران، کرج
2 گروه اقتصاد کشاورزی، دانشکده اقتصاد و توسعه کشاورزی ، دانشگاه تهران، کرج، ایران.
3 مرکز پژوهشهای توسعه و آیندهنگری، تهران، ایران
کلیدواژهها
عنوان مقاله English
نویسندگان English
Introduction
Price volatility in livestock products has always been one of the most significant concerns for policymakers and consumers due to their pivotal role in food security and the supply of societal protein. These products constitute a considerable portion of Iranian households' expenditure basket.
In Iran, economic challenges such as international sanctions, currency fluctuations, the COVID-19 pandemic, and domestic policies like the elimination of subsidized exchange rates have exacerbated the instability of food prices, disproportionately pressuring low-income households .This continuous inflation erodes purchasing power, increases inequality and poverty rates, and can lead to social discontent.
Price changes in these commodities directly and negatively impact the purchasing power of various social strata, especially low-income groups, through two channels: on one hand, they harm the production sector and create financial pressure, and on the other, they reduce consumers' life stability by limiting their ability to plan. These fluctuations increase market risks by creating uncertainty about future prices. Consequently, investment planning becomes difficult, which can lead to a reduction in long-term production and an increased reliance on imports. Food inflation significantly affects household purchasing power and economic welfare and is considered a primary concern for policymakers
Persistence food inflation, characterized by long memory processes, indicates the prolonged impact of price shocks, which complicates efforts to restore price stability . The presence of long memory implies that a shock can have enduring effects on the variable. The goal of the current research is to provide a comprehensive picture of the price persistence of livestock products (beef, mutton, chicken, egg and milk) in Iran.
Considering that the Iranian economy has been affected by significant shocks in recent years, this study also investigates the impact of these specific shocks—including the U.S. withdrawal from the Joint Comprehensive Plan of Action (JCPOA), the COVID-19 pandemic, and Preferential Exchange Rate Removal —on price persistence at both levels (farm and retail). These findings help policymakers, with a deeper understanding of price dynamics, devise more effective strategies for managing price volatility in this critical sector.
Materials and Methods
In the present study, the time-series analysis approach using the ARFIMA (p,d,q) model is employed to investigate the price persistence of livestock products at the farm and retail market levels and to assess the degree of persistence of the shocks' impact. This model is a generalization of the traditional ARIMA models, and its main advantage is its ability to account for fractional and long dependencies, which characterize many economic phenomena. As a powerful econometric framework, the ARFIMA model allows for the analysis of whether a price shock has transitory effects or whether its impacts persist over time and influence future price levels.
The parameter d in the ARFIMA model indicates the level of dependency (or memory) between observations. A higher value of d signifies greater persistence and durability between observations, suggesting that the effects of the shocks remain on prices for a longer duration. The data used include the prices of livestock products (beef, lamb, poultry, eggs, and milk) at the farm and retail levels for the period from April 2014 to March 2024 which were collected from the State Livestock Affairs Logistics Company.
Results and Discussion
The model results indicate that the prices of all livestock products exhibit long memory. This means that past price shocks maintain their effects on future prices for a prolonged period. The analyses reveal significant differences in price persistence between the farm and retail levels. Specifically, the degree of integration (d) for meat is lower at the retail level than at the farm level, and for milk, it is lower at the farm level than at the retail level. This finding is entirely consistent with the results of seasonal unit root tests and indicates the differentiated functioning of market mechanisms at each level.
The results showed that COVID-19 significantly affected price persistence at the farm level, whereas the shock from the Preferential Exchange Rate Removal had lasting effects on price persistence at the retail level. In contrast, the shock from the U.S. withdrawal from the JCPOA had no significant effect on any of the variables.
Conclusion
Based on the obtained results, the following suggestions are presented for policymakers:
Since the results indicate that price persistence patterns are not uniform across different livestock products and market levels (farm and retail), policy approaches must be targeted and tailored to the specific characteristics of each product.
The results show that the degree of integration for lamb and beef is higher at the farm level than at the retail level. Therefore, to protect livestock producers from market fluctuations and external shocks, the government can implem
کلیدواژهها English
