فصلنامه تحقیقات مدلسازی اقتصادی
سال دوم شماره 6 (زمستان 1390)

The effect of equivalence scale on poverty line has been considered as a predetermined parameter in all previous studies about the estimation of poverty lines in Iran. As household’s members can benefit from economies of scale in consumption، the cost of reaching to a given level of welfare does not increase one to one in household scale. So the effect of household scale on poverty line as a predetermined parameter creates bias. The main purpose of this study is to estimate the poverty line regarding the household scale. The utility function and the indirect household expenditures under consumption behavior approach are estimated based on income-expenditure data for 204464 Iranian urban households during2001-2007. Then poverty lines (in nominal and real units) per household scale (1to 10 members) are calculated based on indirect household expenditures.

According to Taylor (1993) rule، the monetary authority responds to deviations of output and of inflation from their targets through nominal interest rate fluctuations regarded as policy instrument. Another specification that has received considerable attention is that policymakers may have asymmetric preferences with regard to their objectives during recessions and expansions. Since according to Law for Usury (Interest) Free Banking of Iran، the objective of the central bank is not the control of interest rate، instead it is money growth rate which is used as an instrument، in this study we introduce a money growth rate reaction function and we use it to test the asymmetry in central bank behavior during recessions and expansions. The estimation results of a Markov Switching model for the period 1367:1 to 1387:2 show that the central bank sensitivity toward output is more during the recessions while its sensitivity toward inflation is more during the expansions.

The number of factors affecting total factor productivity has been increasing far from those which considered in growth models. So، institutional factors have been attracting strong attention of researchers. This paper aims at investigating the effects of these institutional factors together with traditional factors on TFP growth during 1971-2007. For this purpose، we present a State-Space model. Using this approach، TFP has been regarded as a latent variable and in the state equation، we introduced some exogenous variables. Some endogenous variables which were mainly measures of institutional factors have been specified as proxies. Our result show that the introduced measures of institutions such as governance (political stability and accountability) institutions and degree of government intervention together with an older and known institutional factors، such as macroeconomic instability، have significant effects on TFP growth. In addition، the residuals from state-space model (either deterministic or stochastic) were different from the residuals of other models.

Data envelopment analysis (DEA) estimates the relative performance of decision making units (DMUs). This paper uses the idea of the Analytical hierarchy process (AHP) method and fuzzy set theory to modify the model of DEA which can be used to evaluate the performance of business units. In this paper، a new method has been proposed for estimating the performance of DMUs with interval data and weights of data. The models proposed in previous studies have interval data or interval weights of data، so the proposed model has more flexibility than previous studies. Thus، innovation has been done theoretically and the experimental part is for testing the theory. Finally، a method is introduced for ranking the DMUs by computed performance. In order to prove the applicability of the proposed method، a case study for ranking of some Iranian automotive companies products is given. The model results indicate that the proposed model will be useful for practical problems، especially when the number of choices is limited.

Environmental Kuznets Curve (EKC) theory has evolved over several decades from its initial intuitive conception to the complex theoretical models of today. Through successive steps of empirical and theoretical debate، a quadratic relationship between income and environmental degradation has been proposed، criticized، defended، and criticized again. Along the way، each finding have new look at the subject. Critic that is provided by Mazzanti et al. (2007) and Stern (1998) is that instead of attempting to gain insight into the underlying mechanics of an EKC theoretical foundation، there are undue focus on exploring empirical regularities among a large set of variables. These critics from opponent and supporter cause researcher to review their approach and take more concerns on details and methodology of EKC theory that make the way of theoretical works. In this paper، a microeconomics model is provided in which household confront with decision about consumption of dirty and clean goods. It is showed that household make decision in the way that، as income increases، environment pollution rise at first and then fall when household substitute dirty goods by clean goods.

Public-Private Partnerships (PPP) models using the capacities of private sector have provided a background to supply public services and infrastructures in different ways. Transportation sector as a fundamental sector of economic development in Iran needs public-private participation models. For this purpose a theoretical literature of public-private partnerships has been reviewed and then the barriers to the development of such partnerships in transportation sector of Iran economic، infrastructure، legal and social areas were investigated. Finally with AHP، TOPSIS and SAW methods of Multi Criteria Decision Making (MCDM) the barriers were prioritized and their relative importance was analyzed. The results of three methods indicate that factor of financial markets limitations and availability of financing is the main barrier to the development of public-private partnerships. Although there is a little different among the results of TOPSIS in rating some final factors compared to other two methods، by calculating rank correlation coefficient (Spearman) the null hypothesis (the lack of correlation between the results) was rejected and with 99. 75 percent probability all of the result are similar. Ranking results of barriers to the development of public-private partner ships in this study can be taken into consideration in policymaking and determining the requirement to use these models in the fields of transportation and other infrastructural areas.

In this paper، a small scale Factor-Augmented Vector Autoregressive (FAVAR) Model is utilized to analyze the effects of monetary shocks on price level and economic activities in the Iranian housing sector. To analyze the «price level»، four price indices of the housing sector were used and also six indices to estimate the «economic activities» in this sector were determined. The results show that shocks from liquidity and high powered money will have wave-like effects on the housing sector in Iran. The waves have an approximate duration of 5 years which is confirmed by observations of the housing sector in Iran. Also the results show that the effects of the liquidity shocks have more durable effects on the sector in comparison with the high powered money shocks.

This paper aims to determine the optimum price of electricity during restructuring process. We maximized social welfare function subject to market equilibrium، maximum production capacity of each group of power plants، maximum demand of each consumer type and the potential of electricity export and import. The model was run using 2007 monthly and annual data by means of GAMS optimization software. The calculated electricity shadow price for the year 2007 was 371. 2 per KWh. To get more exact results we run the model for each month separately. The results show that the price of electricity in spring and summer is lower than fall and winter، for marginal cost of power provision in winter rises. This is due to substitution of gas by gasoil and other liquid fuels and also reduction of hydropower production. For both intervals the actual price has a significant deviation from optimum price in Iranian power market.