Higher education is an economic good like other goods and services that households, according to their INCOME, have sensitivity to it. This sensitivity is an indicator for assessing household ELASTICITY INCOME for higher education DEMAND. Therefore, in this study the attitude of households toward higher education was examined. The main objective of this study was to calculate higher education INCOME ELASTICITY DEMAND for Iranian households. The major question was: is higher education a kind of luxury, necessary or inferior good for Iranian households? By using a quantitative method and utilizing data from Statistic Center of Iran, the INCOME ELASTICITY DEMAND for urban and rural households during 2005-12 was calculated for 2012 by INCOME deciles. The results showed that the higher the INCOME growth, higher education as luxury goods has become an essential commodity for Iranian households. Consequently, the major hypothesis of this study is accepted. In addition, over time higher education has become an essential commodity for urban and rural households.

The DEMAND for food is estimated within a system framework. The seperability structure of the model is checked by a parametric test. The almost ideal DEMAND system is estimated by seemingly unrelated regression in the static and dynamic version based on the time series data for 1974-2003 in Iran. The results of various specification and misspecification tests suggest that the static version performs poorly as compared with the dynamic version.The results of seperability structure rejected hypothesis saying consumers first allocate their INCOME among different food groups and then within subgroup of meat. The compensated and un-compensated own-price ELASTICITY is negative and the INCOME ELASTICITY is positive.

One of the most important inputs in all economic sectors of Iran is water. The solution to the shortage of water resources in Iran is not more water supply, but an effective solution to adopt policies and measures that change the economic structure and pattern of water consumption. In this study, the INCOME ELASTICITY and price ELASTICITY of Kermanshah urban water DEMAND and the estimation of daily consumption of each person during the period 1392-1397 have been estimated. For this purpose, at first, the general form of water DEMAND function was calculated by maximizing an Aston Gray utility function and was estimated using the VAR model, based on the Johansen method of Kermanshah urban water DEMAND function. According to the results, urban water DEMAND is inversely related to water prices and directly related to INCOME. Price ELASTICITY indicates a negative relationship between price changes and water DEMAND. If the price of water increases by 10%, the DEMAND for it will decrease by 4. 3%. On the other hand, the absolute value of price ELASTICITY and revenue ELASTICITY of water is less than one. Also in this research, ARDL model has been used to investigate the long-term, short-term relationship, error correction test and tensile tests as a complementary and comparative method with VAR model of ARDL model. In both models, the price ELASTICITY is less than one, ie with a 10% increase in price, consumption decreases by less than 10%. The non-zero price ELASTICITY of water indicates that increasing tariffs can be used as a way to reduce water consumption, at least in the short term. The results showed that according to the criterion of the usefulness function of acetone, the minimum water consumption for each subscriber in Kermanshah is about 8. 21 cubic meters (8210 liters) per month. According to the model, this amount is about 273 liters per day.

The trends and developments of energy consumption and planning for energy supply is an inevitable issue for every country. In economics, energy consumption like others variables such as labor and capital, has an important role in production. This clearly justifies its importance in economy and economic activities. Therefore, every country tries to define a security level for energy. This is an important reason why countries apply many methods for calculating and estimating size of energy resources and prices, as well as the supply and DEMAND models of energy. There are several institutions devising models for estimating and forecasting energy. The EIA and IEA, from the costumer side, and OPEC, from the supplier side, are the organizations that have developed world-scale energy models to estimate and forecast trends of energy markets in the different world regions. They also publish reports on a monthly, quarterly and annually basis. The IIES World Energy Model (IWEM) is one of these models that have been developed recently. The IWEM is a long run and econometric model and has four sub-models which estimate and forecast DEMAND, supply and price equations for different energy carriers in different regions and sectors of world. This model is run by Eviews software and is compatible with Windows system. It employs up to 450 equations and relations (about 150 stochastic equations and 300 relations). Two specific features of IWEM make it different from other large scale models: It is user friendly and results are easily accessible. Each sub-model considers a region. Furthermore, every region is divided into different sectors (these sectors are: transportation, industry, commercial-residential and power sector) and equations have been devised for these sectors. This model also has equations for estimating gas DEMAND, supply and price. The estimation of model for period of 1960-2001 and forecasts for 2002-2010 are indicative of an ascending trend for gas in all regions. For example, the table below shows the results of the IIES World Energy Outlook (IWEO) for average growth of natural gas in OECD different regions and sectors.

Iran is located in an arid and semi-arid region and will be joining the 'Thirsty States' by 2025. However, water use efficiency and water services seem to be low and inadequate, as they do not match the emerging conditions of water scarcity. As part of the research efforts required addressing the problems in this area, this paper endeavors to use a simple, efficient, precise, and practical method for determining the INCOME and price ELASTICITY of the domestic drinking water DEMAND. The household INCOME in this method is replaced by a good, measurable substitute index which is the household land and building areas. Log-log functions are presented for different blocks for the statistical period 2001- 2004. Correlation coefficients obtained were above 40% in all the functions. The average INCOME ELASTICITY ranged from 0.704 to 0.411 for the first to the fifth blocks, respectively. This shows that water is a necessary and non-substitutable commodity in the household portfolio. The price DEMAND ELASTICITY was estimated using the modified Pollak-Wales method, price variations over two different time periods, and INCOME ELASTICITY over the statistical period. The price ELASTICITY value varied from - 0.3 to -0.01 for the second to fourth blocks, respectively. This indicates the inELASTICITY or low ELASTICITY of water for current prices.

The high energy intensity and air pollution in Iran have led to the consideration of energy DEMAND management and the factors affecting it since the last decade. In this context, how prices affect energy consumption is of great importance. On the other hand, the price ELASTICITY of energy DEMAND changes over time due to the fluctuation of energy prices, the development of the energy market and economic conditions. Therefore, the main purpose of this paper is to estimate the time-varying price ELASTICITY of energy DEMAND in Iran during 1991-2018. For this purpose, energy DEMAND elasticities were estimated using real non-oil GDP, energy price index and real total energy consumption of Iran and Kalman filter method. The results show that the price ELASTICITY of energy DEMAND has changed between-0. 010 and-0. 043 and its average value is-0. 027. The INCOME ELASTICITY of energy DEMAND has changed between 0. 902 and 0. 13, and its average value is 0. 46. Several important points can be derived from these results: First, energy DEMAND is less elastic to INCOME and price. Second, these elasticities are not constant over time, and ignoring this instability leads to biased estimates. Third, energy prices play an insignificant role in energy consumption in Iran relative to economic growth. Therefore, to improve energy intensity, in addition to energy price reform, special attention should be paid to requirements that increase consumer price sensitivity.

Introduction: Macroeconomic instability, exchange rate volatility, high inflation and consequently rising food price have been critical issues in recent years in Iran’ s economy. Policy inefficiencies, policy inconsistency, and food price fluctuations have affected vulnerable households and low-INCOME groups and increased food poverty, undernourishment and malnutrition. The study of INCOME and price elasticities of food items, especially in different INCOME groups, provides valuable information for policy making. Method: This research, using the approach of the almost ideal DEMAND system, studies the ELASTICITY of food items in the household consumption budget for 2016 and 2018 and compares different INCOME groups. The household INCOME and expenditure from raw household survey data for the years 2016 and 2018. Due to the heterogeneous impact of price changes on DEMAND in different INCOME groups, the study was conducted on different INCOME quantiles. In this respect, we focused on meat, bread, and dairy item. Findings: Results show that bread is identified as an inelastic good and dairy and meat as elastic goods for low-INCOME groups. The results of quantile analysis show that in 2018, bread was a Giffen good for the first quantile and necessary good for the third and the fifth. Discussion: The results indicate that the consumption of animal protein and dairy products is highly sensitive to the price of these goods. An increase in the price of these goods will limit the consumption of these micronutrients in the household food basket or possibly eliminate it in the low-INCOME groups.

In this study, the estimation of price, INCOME and cross elasticities of gas DEMAND in the selected group of high INCOME and middle -INCOME countries in the period of 1990-2020 has been done using the panel data method. The results of the estimation of the model using the fixed effects method showed that gas is an inelastic commodity in the group of selected countries. The price ELASTICITY of natural gas in the group of selected high INCOME and middle-INCOME countries is 0.256077 and 0.196553 respectively. The reaction of gas consumers in the group of selected high-INCOME countries is higher than the group of selected middle-INCOME countries to the same change in the price of gas and also, the results of INCOME ELASTICITY showed that gas is an essential commodity in the group of selected countries. The INCOME ELASTICITY of gas in the group of selected high-INCOME and middle-INCOME countries is 0.355611 and 0.490959, respectively, and finally, the results of cross-ELASTICITY estimation showed that electricity is a substitute for gas in the group of selected countries. The cross-ELASTICITY of gas compared to the price of electricity in the group of selected high-INCOME and middle-INCOME countries is 0.029562 and 0.091683, respectively. The reaction of gas consumers in the group of selected middle-INCOME countries to the same change in INCOME and price of electricity is more than that of the group of selected high-INCOME countries.