فصلنامه اقتصاد مقداری
سال دوازدهم شماره 3 (پیاپی 46، پاییز 1394)

In recent years, the factors influencing the corruption, have attracted more attention among the economists and policy makers, because corruption is one of the main obstacles to economic growth, declining government legitimacy, increased illegal activity and political instability of countries. Therefore the purpose of this study is to estimate the index of corruption in Iran during the period of 1978-2013. In this study, to estimate the index of corruption the fuzzy logic (Fuzzy Logic) that is popular in applications such as ambiguous time series is used. The results show that the index of corruption have been fluctuating in some years but in recent years the trend index of corruption has been upward. The other results of this study show that a two-way causal relationship between underground economy and corruption existed in Iran.

The purpose of this paper Is to examine the impact of uncertainty in macro economy on imports from selected developing countries. Exchange rate fluctuations, growth rate and inflation rate has been considered as indicators of uncertainty in macro economics. Uncertainty in macroeconomics cause uncertain environment in market and therefore creates some changes in the volume of imports. This paper tries to use Panel data model during 1980-2009 years and General autoregressive Conditional heteroskedasticity to measure uncertainty and then examines the impact of uncertainty in macro economy on imports. The results of estimation of models indicate that uncertainty of economy on the rate of imports is effective.

This paper using a dynamic panel data approach investigates the impact of the profitability on the market concentration in the Iranian four-digit textile industries during the years 2000-2007. To this end, we used the profitability and the market concentration degree to measure the market performance and the market structure, respectively. The results of this study indicate that the profitability as a criterion for market performance has a positive effect on the market concentration. In addition, the effect of the export intensity, sales ratio, and investment intensity on the market concentration is positive.

The aim of this paper is to study the effects of minimum wage increase on employment in Iran. For this purpose, we deploy a multi-sector, multi-labor computable general equilibrium model which includes some important assumptions of the labor market such as imperfect mobility of labor, labor-leisure choice, minimum wage and substitution between skilled and unskilled labor. Two types of labor-skilled and unskilled labor- are considered in this model. The model is calibrated based on 2001 Micro Consistent Matrix. Results show that minimum wage increase will decrease unskilled labor employment in all sectors while it will increase skilled labor employment in agriculture and services sectors and decrease skilled labor employment in other sectors.

In many studies, in order to predict economic variables, quantitative methods based on time series data or cross-section data are mostly used. Time series data or cross-section data do not control the heterogeneity of countries, and the possibility of obtaining the risk of biased results exists. Panel data provides more informative data and a more degree of freedom which lead to results and predictions that are more precise. In this study, while considering the significant role and proportion of dried fruits in non-oil exports, the synthetic artificial neural network-panel data method has been used to predict the price of pistachio, raisin and date exports. Then the predictions were compared, using the accuracy criteria, with the regression model (the two-way error component model). The data from ten target markets for each of the dried fruits from 1992 to 2012 were used, and the results of this study show that the new and synthetic artificial neural network-panel data method has a better performance in predicting the price of Iran’s pistachio, raisin and date exports than that of the regression method. Therefore, it is suggested that exporters, policy makers, and researchers use this method in order to predict economic variables.

Inflation as one of the most important considerable problems in economy has many harmful effectssuch as lack of optimum source allocation, retarding the process of economic development and creation of uncertaintyin the future. This study with the topic of "optimal inflation for Iran by using general equlibrium model of Sidrauski" is an attempt to clear one subset of inflation issue. The method of this study is descriptive-analytic. At first, we developed the Sydraskimodel,and for more accordance with reality, some parameters were added and it was solved by using Ramsey optimization method, which is a dynamic general equilibrium method. After gathering and estimating necessary data, the model was established and by using Matlab software,optimization and calibration operations were done. The results of investigation indicate that the optimal inflation, which is capable to bring the most social welfare for Iranian economy, is -0.0196. This rate, which expresses the most welfare, provides Freedman’s optimization formula. The results of theoretical model indicate that, reducing the money creation power of commercial banks by increasing legal reserve rateand population growth can lead to less optimal inflation.