TAXes are the most stable government revenues and they can be used as tools to implement social justice and to encourage investment. The purpose of this article is to determine the OPTIMAL vat RATE by using a neoclassical growth model in Iran. To this end a generalized segmented growth model including household, firm and government was first developed. Using the parameters of the Iranian economy and social accounts matrix (Sam 1395), the mentioned model is calibRATEd and the OPTIMAL TAX RATE is determined in two scenarios in such a way that it receives the most income and has the least disruption. The research method is analytical and using a macroeconomic model. The research model is in the framework of computable general equilibrium model (CGE) and TAX achievement in different scenarios. The results show that the implementation of vat at different RATEs and in two scenarios 5 and 10 percent will increase the general level of prices, reduce GDP, increase government revenue, reduce household income and expenditure, increased total absorption and exchange RATE.

Background: TAXes are not only an important source of government revenue, but also one of the most important policy tools for tobacco control. The present study was designed to determine the OPTIMAL TAX RATE on cigarettes.Methods: A descriptive-analytical study was conducted using the survey data from the Statistics Center of Iran from 2015 to 2019. The survey is carried out every year at the national level and households are selected by three-stage stratified sampling method. The inclusion criteria for our study were based on household information in the study period and its completeness and legibility. The Poisson regression model was used to estimate the factors affecting the quantity of cigarette demand in households with smoker members. The OPTIMAL TAX RATE on cigarettes was calculated based on the concept of Laffer curve. Statistical analysis was performed using Stata version 15.1.Results: The study was performed on 191,648 Iranian households. The cigarette price elasticity of demand was around -0.24. There were statistically significant relationships between the cigarette demand and variables including having a member of 15-18 years in the family; having male member of 19-64 years; having a female member of 19-64 years old; the study periods; age, education level; and job status of the household head (P<0.05). According to the Laffer curve simulation, if cigarette TAX RATE is increased to account for 219% of the retail price, that will maximize incremental TAX revenues at around US$2.39 billion.Conclusion: The government can achieve public health goals as well as maximum TAX revenues by raising cigarette TAXes by almost 200% and raising the average price of a cigarette pack from $1 to about $3.

EXTENDED ABSTRACT INTRODUCTION In most countries, TAXes are the most important source of government revenue. But in Iran, TAXes have long provided a small share of government revenues. Perhaps the most important reason is the existence of oil revenue sources that have put the TAX on the sideline. For this reason, the emphasis has been on reforming the TAX structure. In this regard, the Law on Value Added TAX was implemented in Iran in the second half of 2008 to reform the TAX structure. VAT is a new TAX that was created to reduce the shortcomings of the traditional TAX system and also to increase government revenue. VAT is a type of sales TAX that is levied at various stages of production and distribution of goods and services. The average VAT RATE in different countries is between 5% and 18%. In Iran, since the enactment of the VAT law, there has been a lot of controversy and debate among experts regarding the determination of TAX RATEs. This RATE was set at 3 percent at the time of implementation of the VAT law and was set to increase by one percent each year, so that in 2018 it reached 9 percent. As the TAX RATE increases, so does government revenue from TAX collection. However, this increase in income is limited, and if TAX RATEs exceed a certain point, TAX revenues will decline, because due to high TAX RATEs, people will lose motivation to work. Therefore, it is necessary to determine the TAX RATE that maximizes TAX revenues. It is also necessary to determine the OPTIMAL RATE of this type of TAX so that the government's TAX revenue is maximized but it does not hinder economic growth. The present study was conducted for this purpose.   METHODOLOGY This research was conducted in the period of 2008-2018 using data from 24 provinces whose information was available. The research data related to VAT RATE and government TAX revenue in the period of 2008-2018 was collected from the provincial yearbooks. The year 2008 is the beginning of the implementation of the VAT law and 2018 is the last year that information and statistics were available. Finally, the OPTIMAL VAT RATE in Iranian economy was estimated using data panel method. In this method, first, using Lemmer test, panel data in model estimation was selected. Then, using Hausman test, the estimation with random effects was confirmed. All analysis and model estimations were performed using EViews 9 software.   FINDINGS Findings from the statistical description of the data show that VAT RATE in Iran in 2008 was set at 3% and remained at the same RATE until the end of 2010. From 2010 onward, VAT RATE increased so that in 1394 it reached 9%. From 1394 to 1396, it remained constant. Also, the results of model estimation show that VAT in Iran has lufferel effects; i. e, increasing VAT RATE directly increases the government's TAX revenue and indirectly reduces the government's TAX revenue by reducing production incentive. Therefore, VAT RATE has an OPTIMAL value at which the RATE of government TAX revenue is maximized.   CONCLUSION The OPTIMAL VAT RATE calculated in this study is 10.33%. Considering that VAT RATE has been set at 9% in 1398, increasing this RATE to 10.33% in the coming years is recommended. This will increase the government TAX revenue. An increase in the TAX RATE above this amount will reduce the government TAX revenue. Therefore, exceeding VAT RATE over 10.33% is not suggested.

Environmental health is one of the most important current concerns of people and officials in the world, and all managers and decision-makers believe that this national wealth should be protected not only for the present generation but also for future generations, because industrial pollutants cost the public a lot of money. In Iran, despite the increase in pollutants, no practical decision has been made yet, in this study, which aims to determine the damage and the amount of environmental TAX with the help of library data based on isic codes by SUR method (seemingly irrelevant regression). The estimated cost variables (salary, insurance, TAXes, training, transportation, fuel, repairs) show that more than 0. 95 of the factors affecting the total cost are explained by the above variables in the model and the OPTIMAL green TAX RATE in the whole industrial sector, for every one million tons of production, equivalent to 0. 19%, cement sector, 0. 13%, petrochemical sector, 0. 18%, rubber and plastics, 0. 17%, power plants, 0. 12%. In addition, stone mines 0. 09%, Steel 0. 17, 5%. It is concluded and suggested that the government and responsible agencies can use financial instruments to control pollutants.

In this Article, OPTIMAL VAT RATEs have been calculated for the three different levels of consumption TAX revenue needed by the government. Using the data of 10 income groups of the Iranian rural and urban households in the period (1378-1386) and applying Panel Data approach, the Almost Ideal Demand System (AIDS) were estimated to derive the price and income elasticities. Then, the OPTIMAL VAT RATEs were derived using Diamond & Mirrlees (1997) model and Marginal Social Utility Criteria. The results of the study show that, the TAX RATEs derived for three different levels of revenue as well as for zero level of the Degree of inequality aversion are nearly equal and is about 4 percent, which in turn endorses the one RATE VAT system currently operating in Iran.

Nowadays it is obvious that higher share of TAX revenues in budgeting and its role in developing dynamic economy has been a main criterion of growth in each country. The value added TAX has been focused by policy makers due to its transparent collection. It is crucial to determine OPTIMAL and appropriate TAX RATEs to achieve economic objectives. The underground economy and its activities which are accompanied by false information declaration affect the level of government TAX revenue collections. This paper seeks to determine OPTIMAL TAX RATEs in three introduced models by using the Particle Swarm Optimization (PSO) Algorithm and the current data during the period 2008-2017 in two different conditions of underground economy and its absence. The results indicate that government collects near OPTIMAL value added TAX by VAT RATE optimization. On the other hand, the higher changes in value added TAX RATEs have significantly positive effect on underground economy.

Introduction: TAX as a resource of government revenue, is one of the most important devices to redistribute income and reduce the gap between the poor and the rich. Meanwhile, direct TAX, exclusively income TAX, is more considered than the other TAXes for its simple accessibility. The importance of TAXation from person income and in different viewpoints in distributive justice has led this discussion to the identification of OPTIMAL income TAX features in last four decades.Method: It is tried in this paper to study the OPTIMAL income TAX by adopting the Rawlsian social welfare criterion and estimate its RATE in Iran by using ARDL approach for the period 1350-85.Findings: The findings of this study suggest that the effective OPTIMAL income TAX RATE in short-term (long-term) is 3.1% (1.26%) in Iran.Discussion: It is resulted that TAXation by using the estimated RATEs on persons' income and then redistribution to all members of society leads to the maximization of social welfare in Iran.

In this study we have investigated income and price elastisities of consumption and selling of household of cities in Iran in period 1353 until 1385, by using Almost Ideal Demand System and Habit Formation Linear Expenditure system. The result of study by analysis of toll aggregation current trend shows that consumption and selling TAX RATEs in Iran, determine without allocation and distributive effects of indirect TAXes and also income and price elasticity.

Todays, the importance of TAXes as the main source of government revenue has been approved by economic policymakers and therefore, designing an OPTIMAL TAX system to achieve this subject is essential. Governments are looking for ways to receive their target TAXes from TAXpayers at the lowest possible cost and at the declaration TAX. TAXpayers, on the other hand, seek to postponed their TAXes as much as possible and make the most of the effects of inflation. This paper models the game between TAXpayers and TAX affairs organization. The results show that the Nash equilibrium in the designed game occurs where TAXpayers declare their declared TAX less than the diagnostic TAX and careful handling by TAX affairs organization. In the next step, the equilibrium is somewhere that TAXpayers continued their protest until the step of the Court of Justice (the dominant stRATEgy) and TAX affairs organization agrees with them (the dominant stRATEgy). Finally, the OPTIMAL fine RATE for the TAX affairs organization was determined until TAXpayers do not continue their protest to buy time and devalue the amount paid and agree at the initial stage 238.

Introduction: One of the challenges faced by governments in the last century is environmental crisis such as greenhouse gasses. Due to population growth in the world, human activities including agriculture and dairy cattle industry for providing food security for peoples have increased and caused the more pollution and greenhouse gasses emission. to the extent that the amount of greenhouse gasses released by agriculture and dairy cattle's activities in the world is more than greenhouse gasses produced by transportation activities. The main agricultural greenhouse gases (GHG) are methane and nitrous oxide. Methane is produced in the rumen of the cows by methanogen microbes and are naturally present in all ruminant animals. Most methane is emitted when cattle burp. Nitrous Oxide is emitted from soil when urine, faeces and fertilizers broken down by microbes in the soil. Governments and policy makers, by applying policies and programs are struggling to overcome the problems encountered in the environmental field and reduce the negative and harmful effects of human functions on the environment. One of the ways to control and reduce environmental damages such as greenhouse gasses is using economic tools and policies such as TAXes on environmental degradation activities. Materials and Methods: This study aimed to evaluate the appropriate green TAX RATE on methane emissions in dairy cattle industry in Hamedan province. Therefore, of 44 dairy farms in Hamedan province were chosen by simple sampling method and data were collected about the cost of producing this section through questionnaires during 1395-96. By calculating the share of costs using shephard lemma and the Iterative Seemingly Unrelated Regressions method (ISUR), the cost function and cost sharing equations were estimated as a system. The advantage of the current model is that the ISUR estimators utilize the information present in the error correlation of the cross regressions (or equations) and consequently are more efficient than single equation estimation methods such as ordinary least squares. In the selected model the price of animal feed (Pfood(, price of medicine and vaccination )Pmedicin(, price of energy(Pene( and labor wage (Pwag(, are the independent variables. Results and Discussion: The results indicated that about 52% of the pattern coefficients were significant. Thus using Translog cost function is appropriate for estimating the cost function in dairy cattle units. The calculated R2 criterion for Translog cost function is estimated about 0. 99 in this research, which implies that about 99 percent of the variations of milk’ s total cost are defined by the variables including animal feed price, labor wage, energy price and the price of medicine and vaccination. Parameters for the input share equations including animal feed price, labor wage, energy price and the price of medicine and vaccination, are calculated respectively as 0. 53, 0. 36, 0. 64, 0. 57 and 0. 34 for the income share equation. The adjusted coefficient of determination, ( ) for the Translog cost function, is about 0. 98, and parameters for the input share equations including animal feed price, labor wage, energy price and the price of medicine and vaccination is respectively 0. 47, 0. 28, 0. 47, 0. 36 and 0. 22 for the income share equation. Based on the results, the D. W of the equation is 1. 98, that indicates the fitted regression is true and there is no autoregressions between residuals and independent variables. Conclusion: Based on this study results, the appropriate green TAX RATE for methane emissions in the dairy cattle industry is 1. 1% per kilogram of milk production. The results revealed a negative relationship among green TAX RATE and pollution emissions coefficient and marginal cost of production. Also, a positive relationship between green TAX RATE and the output price has been detected. This signifies that by increasing green TAX RATE, the emission of pollutions by dairy cattles is reduced. So putting emphasize on the application of green TAXes in order to reduce emissions of methane greenhouse gas. It is also recommended that relevant organizations such as the country's environmental organization, by examining the prevalent infrastructure in the country and providing conditions, use green TAXes as an economic tool for controlling and reducing environmental pollution. Moreover, in the feasibility studies and the pre-construction of the generating unit, the green TAX should be considered in the evaluations.