فصلنامه مدلسازی اقتصادی
سال پنجم شماره 2 (پیاپی 14، تابستان 1390)

This study was to investigate, turning points in Business Cycles in the economy of Iran using seasonal date during (1981:1-2008:2). To make it practical Autoregressive Markov Switching Model by Hamilton (1989) was used. Today this approach is used in many advanced countries in order to identify and dating of cycle. Results showed that in that period in three junctures four records happened. The longest records are during [1991:2-1998:2], with the duration of 7 seasons. In addition to that results showed that in under discussion period every time a record happens in countries for about 1.74 seasons. While the appearance of every Boom in under discussion period in the economy of Iran continued 6.66 seasons.

Based on the efficiency of wage hypothesis, this paper examines the determinants of wage dispersion of large manufacturing industries using a panel of 4-digit ISIC data during the period of 1998-2007 in Iran. The findings explain that there is a significant difference between wages in the sampled data. By eliminating the effects of individual measured and firm characteristics such as gender, education, expert, experience, efficiency, firm size and so on. The differences in wages have remained significant yet. The results confirm the efficiency of wage theory, in which the wages dispersion cannot merely attribute to labor force characteristics.

The effect of effective variables on the share of new automobile in household consumption basket has been considered and analyzed in this research during 1991-2007 by using Almost Ideal Demand System. Results of estimating seemingly unrelated regression represents that the real expenditure changes of household, household dimension and cost changes of other goods will affect this share. The study of expenditure elasticity and price elasticity estimation, respectively, shows the luxuriousness and elasticity of automobile in Iran economy. The results of automobile cross-price elasticity estimation by other groups explain that automobile is an alternate to three groups of food, non-food and housing, that is, the increase of automobile price will cause to increase the expenditure of household basket in all three groups share. More importantly is the point that the two groups of food and housing are the complements to automobile.

The purpose of this study is to estimate the relationship between economic growth and electricity consumption growth in the selected oil exporting countries during 1972-2008 using both country time series and panel data. The empirical results based on panel data indicated that there is a mono-directional short-run causality running from electricity consumption growth to economic growth and a bi-directional long-run causality between electricity consumption growth and economic growth. The findings implied that economic growth in the selected exporting oil countries is highly depended to the electricity energy, and thus, electricity conservation policies will have a reverse effect on their economic growth.

This study investigates the factors that influence the expenditure of consuming non-durable goods in the economy of Iran. the importance of non durable consumer goods in the basket of household caused to identify the factors affecting the consumption of these goods. By statistical time series during 1979-2007, a model was estimated by Vector Auto Regression method. Factors which affect the marginal expenditure of non durable goods include disposable income, wealth, inflation, index of durable goods to non-durable goods and the real interest rate. In this regard, information and data of the Central Bank of Islamic Republic of Iran were used. The results stated that by increasing the wealth and income, the consumption of non-durable goods will be increased. Also, any increase in the index of durable goods to non-durable goods will grow non-durable goods consumption.

The purpose of this paper is to examine the relationship between crude oil demand and economic growth in Middle East by panel unit root and co-integration developed techniques during 1980-2007. By developing a model, the crude oil demand, oil price and GDP and their growth rates will be explained. In continue, we are going to estimate two various models for oil demand function and the effect of economic growth on Middle East oil demand. The findings represent that the demand function is asymmetric in respect to price and income. Also, economic growth rate is the most important factor for increasing crude oil consumption in Middle East countries. On the other hand, these countries’ oil demand elasticity based upon the price and income is low, but income elasticity is higher than price. However, the findings suggest that oil demand is more important than economic growth. It is because of these countries’ disability in replacing crude oil by new energy sources.

One of the most important objectives of all economic Companies is to get maximum returns of available resources and to achieve high level of productivity. This study is done in order to measure the total factor productivity in Sari Khosh Noosh Company during 2003-2009 by using monthly data and production function. At first, we took the data of capital stock based on exponential trend. Then, different types of functions were estimated, and finally chose Cobb-Douglas production function as the best form. To guarantee avoiding spurious regression, co-integration tests are used. Ultimately, by using Kenderik index, we calculated the total factor productivity and its growth rate. The results explained that, during of this period, the total productivity of the company has decreased.