Journal of Economic Modeling Research

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In the current structure of world economy, imports play an important role in the economic development strategy. Although taking the suitable policies for the imports of goods and services is important, but taking the correct strategy is subject to factors affecting imports. In the most of empirical studies, imports are a function of real income and real exchange rate. So, the effect of income inequality on imports of goods and services has less been investigated. Whereas, increase in income inequality causes an increase in the purchasing power of high income people and demand for imported luxury goods and also causes a change in the composition of domestic and imported consuming goods. This study examine the effect of income inequality on import of goods and services in 17 developed countries and 18 developing countries in the period 1990-2010 using generalized method of moment (GMM) analysis. The results indicate that there is a positive relationship between income inequality and imports of goods and services in developed countries while this relation is negative in developing countries. Furthermore, the relationship between GDP and imports of goods and services is positive in both groups of countries, while the relationship between real exchange rate and imports of goods and services is negative in both groups. Thus, policy makers should redistribute income and wealth in favor of the low income people and motivate them to participate in the production sectors, reduce the inequality gap and improve their competitiveness power in the market and enhance the income from the abroad.

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The structure-conduct-performance (SCP) paradigm has constituted an enduring empirical tradition in empirical industrial economics and has the advantage of clarifying the basic building blocks of the competitive mechanisms. This paper presents a SCP model to estimate causes and effects in Iranian manufacturing industry in 2009. The model used in this paper is a system of four simultaneous equations: agglomeration as the standard measure of structure, advertising and R&D as the standard measure of conduct and profitability as the standard measure of performance. Using the data from a sample of Iranian industries, three-stage least squares results indicate that: a) Advertisement has positive and significant impacts on agglomeration and profitability. b) Profitability has positive and significant impacts on agglomeration and advertisement. c) Agglomeration has positive and significant impact on profitability and also a negative impact on advertisement.

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The main objective ofthisstudy  is to evaluatethe effect offirm size, beta, financial leverageon the performance offirms listed inTehran Stock Exchangeinfourbasic metals, petrochemicals, cementandmedicine industries. The44companiesintheperiod 2007 to 2012 have beenselected as sample in theTehran Stock Exchange. Todo study,the relationshipbetween the variables, usingthesoftwareEviews 8assessmenttest. Toestimate themodel, theF testLimerto select the bestmodel is used thecombined data. The results of this research indicate a significant and negative relationship between financial leverage on corporate performance in the industries of basic metals, petrochemical, cement, pharmaceuticals. The relationship between beta and corporate performance in Basic metalsandpetrochemicalindustries is positive and significantandnot significantinthe cement industryand medicine. The relationship betweenfirm size and corporate performancein thebasic metals, petrochemicaland pharmaceuticalindustries is positive and significant and cement industry is negativeand significant.

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