فصلنامه اقتصاد مقداری
سال هشتم شماره 1 (پیاپی 28، بهار 1390)

The main objective of this research is to identify the most propulsive industrial cluster in Tehran Province. For this purpose we have screened 111 industries in three steps. In the first step we have identified 58 industries which their location quotient is more than one. In the second step we have selected those industries which have strong links with the other sectors using input-output table and information which we have collected in our sample survey. At the end of this stage 17 industries were left. In the third step we have identified the propulsive cluster by drawing spider diagrams for 17 industries and measuring their surface. At this stage we have used 15 variables as indicators of industrial performance. At the end of third stage we have concluded that the auto industry and its supplier industries is a propulsive industrial cluster in Tehran province.

Empirical studies often employ Solow method to calculate productivity. However, potential correlation between inputs and the unobserved firm-specific productivity shocks in the estimation of production function parameters leads to a biased estimation. This implies that firms that have a large positive productivity shock may respond by using more inputs. In recent years, several techniques offering improvements over Ordinary Least Squares have been proposed for estimating production functions. These methods offer simultaneity bias and selection bias corrections not accounted for in an OLS framework. In this paper, we review the econometrics methodology associated with estimation of productivity, and use an econometrics method to control simultaneity bias and selection bias problems. We estimate the productivity of firms using Levinsohn and Petrin (2003) method and panel data for 10 selected 2-digit (ISIC2) manufacturing industries for the period 2000-2007. The results show that the average productivity growth rate is 1.79 per cent with the highest rate of 9.62 percent in 2001 and the lowest of rate -3.98 percent in 2002. Among the manufacturing industries, other non-metallic mineral products and textiles have the highest productivity growth and rubber and plastic products and electrical machinery and apparatus have the lowest productivity growth.

The aim of the present article is to study the reliability test of monetary approach to the exchange rate and balance of payments in the Iranian economics, based on which the flexibility exchange rate system and fixed exchange rate system, the balance of payments is of monetary root which sometimes is considered of importance for monetary policy making. Thus, in order to examine the above-mentioned hypothesis in Iranian economics, in this study, with regard to the dual exchange rate in the Iranian economics, the reliability test with regard to the interaction of official versus unofficial exchange markets on one another we used a model equally tailored for the dual exchange rate systems, being monetary based exchange rates and balance of payments and applying a simultaneous equation system, they were tested. The results of these tests show that although PPP theory is of weak validity in the Iranian economics in the long run, the monetary approach of the exchange rate and the balance of payments are not of significant validity (reliability) and if being monetary based, exchange rate fluctuations in the free market have a higher validity.

In this paper has been used concentration index, cost disadvantage ratio(CDR(, minimum efficient scale (MES) and social cost indices in order to evaluate the water cooler market structure and performance. The survey results indicate that there are low degree of competition between firms in this industry and barriers to entry is high. Also, most firms have not benefited from economies of scale. Harberger and Posner indice show that welfar cost of monopoly in this industry is high.

In this Paper we have used a Panel Data of two digit ISIC classsification of Large Iranian Manufacturing industried for the period 1373-86 to test the impact of demand shocks on the prices of manufacturd good industries. The result indicate that while positive shocks were effective influencing prices, probably reflecting their flexibility,the negative shocks however, have shown mixes results.While negative shocks lead to the decline of prices in such industries as electirical machinery and transport equipments, other industrial branches ofmanufacturing industries have,however did not respond. Our study also show that while the impact of demand shocks has had asymmetrical impact on industries such as non-metalic minerals, electical machinery and transport equipments, such asymmetry however,has not been realised elsewhere in other manufacturing industries. Finally,our rfinding clearly indicate that the intensity of shocks has not been the same in all branches.

Due to the significant effects of velocity of money and liquidity on economic factors, prediction of behavior of these variables has become necessary for decision making. The aim of this research is to specify and estimate factors affecting velocity of liquidity and velocity of money in Iran based on Friedman’s model of demand for money, during 1971-2003. To this end such factors as exchange rate, expected inflation rate, national income, income distribution and degree of banking system development have been considered; and the autoregressive distributed lag model (ARDL) has been applied to estimate the functions of money velocity and velocity of liquidity. The findings of the research, overall, showed that real national income, interest rate, fair distribution of income and banking system development have significant positive relationship with velocity of both money and liquidity; while exchange rate has negative effect on velocity of liquidity, but not on velocity of money. Both velocity of money and liquidity have not been affected by expected inflation rate. The velocity of money and liquidity in Iran’s economy follow U-shaped curve.

The present paper describes the Uzawa (1965)–Lucas (1988) type two-sector model of endogenous growth, in which morover goods and services sector emphasizes also the production of human capital, as well as simulates the time paths of macro variables assuming that the Iranian economy behaves under the hypothesis of denoted model. Therefore it's practiced on dynamic optimization and solving the control problem of maximization the present value of representative agent’s flow of future utility (due consumption) in infinite horizon subject to constraints in physical and human formation using the pontryagain's maximum princliple. Then, for the differential equations system obtained, the dynamics, the existence and determinacy of the steady state, analyzing also the balanced growth paths are studied in two cases parametric and numeric with estimated values for Iranian economy. By using Iranian economy available data in period 1974-2007 various coefficients have been estimated and time paths of GDP and other variables simulated. The results of this study indicate that on the balanced growth path the real GDP annual growth rate in Iran is about 4.7%. Furthermore, an increase in technological parameter for education sector and output elasticity with respect to human capital can makes increase in this rate of growth and economy moves to the higher balanced growth path so that this subject confirms the role and importance of human capital in economic growth.