متغیرهای کلان اقتصادی موثر بر تورم مواد غذایی در ایران: رویکرد tvp-var

هدف مطالعه حاضر بررسی اثر متغیرهای کلان اقتصادی بر تورم مواد غذایی در ایران بود. بدین منظور، از داده‌های فصلی دوره زمانی 1380 تا 1399 و مدل خودرگرسیون برداری با ضرایب متغیر در طول زمان (tvp-var) استفاده شد. نتایج به‏‌دست‏‌آمده از برآورد مدل tvp-var نشان داد که اثر متغیرهای کلان اقتصادی بر تورم مواد غذایی در طول زمان متغیر است. بر اساس این نتایج، نرخ رشد اقتصادی بر تورم مواد غذایی اثر منفی دارد و این اثر منفی در طول زمان افزایش می‌یابد. از سوی دیگر، تورم مواد غذایی نسبت به یک انحراف معیار تکانه (شوک) در نرخ رشد نقدینگی و نرخ بهره اثر مثبت نشان داده و این اثر پایدار بوده است. نتایج، همچنین، نشان داد که با افزایش نرخ ارز، تورم مواد غذایی نیز افزایش می‏‌یابد و این اثر در طول زمان با افزایش مواجه شده است. البته، افزایش سرمایه‌گذاری به کاهش تورم مواد غذایی منجر شده و اثر منفی آن در طول زمان افزایشی است. این نتیجه دارای اهمیت است که افزایش تورم مواد غذایی در یک نقطه از زمان اثر افزایشی پایدار بر تورم مواد غذایی در دوره ‌های آتی دارد. از این‏‌رو، پیشنهاد می ‌شود که با بهبود زیرساخت‌های تولید محصولات غذایی از جمله زیرساخت ‌های فناوری در بخش کشاورزی، ذخیره‌‎ سازی و صنایع تبدیلی، از افزایش تورم مواد غذایی و اثرات پویا و پایدار آن بر امنیت غذایی و سلامت جامعه جلوگیری شود.‌

macroeconomic determinants of food inflation in iran: tvp-var approach

introduction: inflation is one of the major economic problems in developing countries as well as emerging economies. therefore, ensuring stable prices is always one of the main goals of the monetary authorities and indeed the government. meanwhile, inflation is particularly important in the food sector, because the vital and constant human need for food increases the vulnerability of low-income people and makes them face a serious challenge in meeting their life needs. factors affecting food inflation can be examined from two viewpoints: structuralists and monetarists. structuralists believe that real impulses in certain sectors of the economy cause price increases in that sector, and this issue is especially important in developing countries. according to this view, factors such as the elasticity of the supply of agricultural products, currency restrictions, wages and high prices in the food sector result in inflation and its sustainability. on the other hand, monetarists believe that monetary policies cause inflation in various sectors, including the food sector. these policies are carried out in order to regulate the value of money, control the interest rate and influence the level of inflation and social employment. in general, monetary policies can have direct and indirect effects on food inflation in a country by adjusting factors such as interest rates, currency value, and the amount of money in circulation. azamzadeh shooroki & khalilian (2010) investigated the effect of monetary policies on the food price index in iran using the ardl model. the results of this study also showed that there was a long-term relationship between monetary policy variables and the food price index, and the food price index had a positive relationship with the interest rate, liquidity and exchange rate. ghahremanzadeh et al. (2016) investigated the effect of macroeconomic variables on food inflation in iran using the structural vector error correction model (svecm). the results of this study showed that in the long term, the added value shock of the agricultural sector had a negative and significant effect and the amount of money had a positive and significant effect on food inflation. in his study, de haan (2020) examined the effect of monetary policies on inflation and expected inflation. in this study, using an econometric model, it was shown that both people’s information and monetary policies could affect expected inflation. accordingly, this study would be able to fill this research gap by using the vector autoregression approach with time-varying coefficients known as time-varying parameter vector auto-regression (tvp-var) model and provide policy makers with practical results of dynamic changes in the effect of macro variables on food inflation. therefore, this study aimed at investigating the impact of macroeconomic variables on food inflation. macroeconomic variables considered in the model of this study included economic growth rate (pishbahar & baghestani, 2014), interest rate, liquidity growth and investment (ismaya & anugrah, 2018) and exchange rate.materials and methods: one of the methods that is used more recently in economic literature is the tvp-var model. the difference between this model and the models of fixed var coefficients is that it allows changes in the parameters over time and has the ability to flex the coefficients according to changes in conditions, structural failures and cyclical changes; therefore, it will bring more accurate results. the initial var model introduced by sims (1980) was one of the important models for investigating the relationship between various economic variables using shock-reaction functions. results and discussion: in order to test the unit root, considering the seasonality of the investigated data, the hegy test was used to check the reliability of the variables.