کارایی

The need to achieve high efficiency in the country's electricity industry is vital due to limited resources, increasing demand for electricity, strong dependence of other industries on this industry and environmental issues. Considering that thermal power plants play a key role in the country's electricity supply by using fossil fuels, the purpose of this study is to compare the technical and environmental efficiency of selected thermal power plants in the country during the years 1389-1397. In this study, non-parametric practical method and data envelopment analysis method with output-oriented approach are used. It was 71.9% and 87.8%. The study of the average bio-efficiency of these power plants during this period shows that this efficiency has been between 71 and 83.8%. During the period under review, Rey power plant has always had the lowest technical and bio-efficiency. The inefficiency of this power plant has been due to managerial and scale inefficiencies both. The results show that technical efficiency in 1390 and bio-efficiency in 1395 have decreased simultaneously for various reasons such as managerial inefficiency or scale inefficiency or both. The amount of carbon dioxide emissions in 1392 was higher than other years under review, which was due to the reduction of natural gas consumption. Also, the amount of sulfur dioxide emissions during the years 1390-92 due to high consumption of fuel oil and gas oil was more than other years that this method of fuel consumption has reduced the bio-efficiency of power plants in 1392. The same results confirm that based on the three defined scenarios, the coded prices in different scenarios are estimated at 982, 827 and 780 Rials, respectively. Based on the results, it can be said that pricing based on final cost has left the industry with a deficit. In other words, in terms of the final cost pricing method, sufficient return is not provided, and based on this, cryptographic pricing can be a pricing method Be the background.

Despite the conceptual prominence of institutional congruence within scholarly literature, a methodical quantification of its dynamics has hitherto remained an elusive endeavor. This study, employing the metric of cosine similarity and anchoring itself in the paradigm of good governance, seeks to formulate a systematic measure of institutional congruence. Furthermore, utilizing the Generalized Least Squares (GLS) approach, it examines both the direct and interactive effects of institutional congruence on key economic variables—namely, natural resource revenues, banking credit, and energy consumption—within developing countries over the period from 2002 to 2016. The findings of this investigation reveal an intriguing paradox: while the transient efficiency of the examined economies registers at a relatively elevated level (0.879), their persistence efficiency remains markedly lower (0.342), underscoring a fundamental structural inefficiency. Beyond this, the results attest to the presence of the well-documented phenomena of resource curse and financial curse afflicting these nations. Amidst such constraints, institutional congruence exerts a positive and significant influence on persistence efficiency, mitigating, to a discernible extent, the adverse repercussions of the resource curse. Conversely, its interaction with energy consumption enhances efficiency and contributes to the reduction of energy imbalances. Yet, within the financial domain, a paradox emerges: rather than alleviating the financial curse, institutional congruence exacerbates it. This apparent contradiction finds its roots in the very architecture of the governance indices—while in areas such as political stability and governmental effectiveness, they facilitate the prudent management of natural and energy resources, in the financial sector, their emphasis on deregulation and financial liberalization engenders a misalignment with the institutional background of developing economies, thus giving rise to new systemic challenges. The overarching implications of this study underscore a nuanced reality: while the archetype of good governance proves efficacious in domains such as resource and energy management, its application to financial structures necessitates recalibration and contextual adaptation. Accordingly, policymakers are urged to exercise prudence in embracing wholesale deregulation, instead designing institutional reforms attuned to the unique economic and structural particularities of their respective nations—lest the specter of financial curse deepens further.

The banking industry is one of the most important sectors of any economy, because banks are the main pillars of financial markets, along with the stock market and insurance, as an intermediary for financial resources.The aim of this study is to investigate the interrelationships between risk, competition and efficiency among banks. The current research is applied and from the methodological point of view, the correlation is causal type (post-event). The statistical population of the research was all the banks admitted to the Tehran Stock Exchange, and finally 13 banks were selected as the sample of the research and were examined in a period of 9 years between 1392 and 1400. The approach used in this research is regression using simultaneous equations. Six hypotheses were proposed in the present study. The results of the research hypotheses test showed that there is a reciprocal relationship between risk and banking competition. Also, there is an inverse relationship between efficiency and risk of banks, and finally, there is a positive relationship between efficiency and banking competition.

The purpose of this study is to investigating the relative efficiency of commercial banks in the Iraqi Stock Market using Data Envelopment Analysis method.

Design/methodology/approach: 

Commercial banks in the Iraqi stock market were used to test the hypotheses. The final sample covers 11 banks between 2015 and 2022. In this model of data envelopment analysis, the hypothetical unit that is on the efficiency limit is called the virtual unit. The value of λ indicates the combination of reference units used to make the virtual unit of each unit. Then, the amount of excess input in each of the inefficient units and the amount of output deficiency in each of the inefficient units are calculated. Finally, the target values, which are the optimal input and output values, are calculated.

The proposed model that was applied to commercial banks in the Iraqi stock market in the desired period of time, adopts a limited approach to target unit weights for DEA which resulted in the target values that is the optimal values of inputs and outputs.

Originality/value: 

In the banking sector, the relationship between inputs and outputs is complex. Therefore, by strategic selecting, the optimal weights of the input and output, we can optimizing the efficiency of the decision units (DMU). This method effectively examines the complexities related to the inputs and outputs of homogeneous units using conventional data envelopment analysis (DEA) models to evaluate the efficiency of these units. In addition, this paper further advances the literature by examining the relative efficiency of commercial banks in the Iraqi stock market in the context of the emerging market, Iraq.

This research investigates the effect of financial health and macroeconomic indicators on the profitability, efficiency and productivity of Iran’s banks. The statistical population in this research is private and government banks listed on the Tehran Stock Exchange. For this purpose, 20 banks were studied during the period 2013-2021, using the panel data method. The results of the data analysis show that the capital adequacy ratio has a negative and significant effect on the efficiency of the studied banks. Conversely, the quality of the bank's assets, the quality of the bank's management, and the quality of the bank's liquidity have a positive and significant effect on the technical efficiency of the bank. Moreover, the results indicate that interest rate, inflation rate, exchange rate and GDP per capita, as macroeconomic indicators, have a positive and significant effect on the technical efficiency of the bank. Financial health indicators such as capital adequacy ratio, bank assets, bank management quality and liquidity quality have a positive and significant effect on bank profitability and productivity. Macroeconomic indicators such as interest rate, inflation rate, exchange rate and GDP per capita affect positively and significantly the bank's profitability and productivity, while the exchange rate shows a negative and significant effect.

An exchange-traded fund (ETF) is a major innovation in all global financial markets since the first of these funds was launched in 1989 in the Canadian stock market. It was then introduced to the US market in 1993. In our country, too, we are at the turning point of launching investment funds from 1992 onwards. The purpose of this study is to evaluate the pricing efficiency of government funds with the approach of positivist-deductive research philosophy in which data are collected, analyzed, and interpreted to examine the answers to questions. Ordinary least squares (OLS) regression has been used to analyze pricing efficiency and sustainability. The results show that government ETFs are not well designed for investors due to diversity and are probably not marketable well due to low trading volume and market price delays in reflecting net asset value (NAV). On the other hand, these funds are traded at a lower value than their NAVs on average, and the deviation of ETF prices from NAV (permium or discount) for the financial intermediation fund until the third day and for the refining fund until the second day from It does not disappear. The results also showed that between the volume of government ETF transactions and deviations; there was a positive and significant relationship between ETF returns and simultaneous deviations and finally a negative and significant relationship between returns and deviations with interruption. These findings can be interpreted as evidence of the weak-form efficiency of government ETFs.

In this paper, the efficiency of the private sector response to the economic-political changes of Iran's public sector in the areas of immigration, capital flight and population growth rate change has been investigated, during the forty-four years after the Islamic Revolution. For this purpose, the private sector in every year has been considered as an independent decisionmaking unit, and its response efficiency has been calculated using the data envelopment analysis. Political stability, economic stability, political development and economic development are used as the inputs and migration, capital flight and population growth rate change are used as the outputs of this decision making unit. This paper, has been used the Mann-Whitney test to prove the meaningfully of the private sector's reaction efficiency changes. The results of this research show that the efficiency of the private sector reaction has been meaningful throughout the investigation period, and this efficiency has been increased in the first and second decades after the revolution, comparing with itself, and it has been almost stable, after reaching the maximum.

The influence of the type of political structure on the emergence of the resource curse is one of the most important topics that have been discussed about this phenomenon. Most researches have concluded that democracy can prevent the emergence of the resource curse, and vice versa, dictatorial and autocratic systems provide the conditions for the emergence of the resource curse. Of course, the reverse of this relationship has also been discussed, that is, the curse of resources can be an obstacle to democracy and instead a source of dictatorship. Oil revenues in particular and natural resources in general have changed and complicated the institutional relations between the state and the society. The interaction between state and society in oil countries is fluctuating between tyranny and oil democracy. Using two methods of stochastic frontier analysis (SFA) and game theory, the present research shows how natural resource revenues interact with political stability and the voice and accountability, and influence inefficiency and minimize the possibilities of realizing democracy in these countries. Based on this, the oil countries must simultaneously reduce their dependence on oil revenues and, on the other hand, improve structural and institutional reforms.

The state of development of technology in today's world is such that the development process and the future of the world in the field of technology cannot be accurately predicted. In the meantime, blockchain technology has been highly regarded as a revolutionary technology. This technology is a protocol that allows information to be exchanged directly between contracting parties in a network without the need for intermediaries. Blockchain has been one of the most important technology trends in recent years, and banking is one of those sectors that many experts believe will accept major changes from blockchain technology. Considering the revolutionary impact that blockchain technology can have on the banking system, it will be very important to examine the impact of this technology on the banking system, which represents how to create, present and acquire value in this sector. The purpose of this research is to investigate the impact of this technology in the banking system. In order to achieve this goal, the method of data collection is the type of document-library research and sample statistics, and it is quantitative-qualitative in nature, and the method is a survey, and the tools used are questionnaires and field observations. According to this research, it confirms the effectiveness of blockchain technology on the banking system. Finally, considering that blockchain technology will challenge almost all the core sectors of the banking system, it is necessary for banks to adopt a suitable strategy to deal with the threats and use the opportunities resulting from this technology.

Unlike conventional banking, whose the main goal is to maximize profits based on the loans granted, Islamic banks operate based on the laws and rules of Islamic jurisprudence, in which the use of interest is prohibited. It was precisely due to this characteristic of Islamic banking that many experts were hesitant about its continued existence when the first Islamic bank was established in 1963 and predicted that interest-free banking would not last long. Despite these doubts, Islamic banks are now the fastest growing and developing financial industry in the world.
The basic question here is whether Islamic banking can meet the monetary and banking needs of the economy despite conventional banking? Do Islamic banks have the necessary stability and efficiency? In general, factors such as the ceiling of granted loans, rate of return on assets, rate of return on shares, value of bank assets,diferent types of bank expenses and various other factors can cause differences in the efficiency and performance of banks. Answering to these questions requires investigating the performance of Islamic banking compared to conventional banking.
In order to investigate the performance of Islamic banking compared to conventional banking, we used four different approaches: Data Envelopment Analysis (DEA), Stochastic Frontier Analysis (SFA), Markowitz Model, and Capital Asset Pricing Model (CAPM). DEA approach is one of the non-parametric methods based on mathematical methods and linear programming to measure the efficiency of decision-making units. In contrast, SFA is a parametric method based on econometrics and production function estimation to evaulate the efficiency of decision making units. Then we used the Markowitz model to obtain the optimal rate of return of banking stocks and unsystematic risk, as well as CAPM to find the optimal rate of return of banking stocks and systematic risk.

In order to evaluate the technical efficiency of banks based on DEA and SFA methods, the input and output variables of each model have been introduced, which include three input variables and three output variables in DEA method and three input variables with an output variable in SFA method. In the next stage, the following steps were taken to perform the Markowitz model optimization process:Some classes of the assets that are considered to be invested must be selected and according to the limitations of the Markowitz model and considerations related to the selection of variables, and collection of the research statistical sample, during developing the appropriate mathematical and statistical model, the optimization process is performed.
Expected returns are estimated for each class of assets.
The risk of each class of assets is estimated.
The process of optimization and graphical structure are performed to find the efficient frontier, based on which, the set of efficient and profitable assets is determined.
By implementing the mentioned steps and using the time series data related to the rate of return on shares of each of the banks from 2012 to 2020, the average and standard deviation related to the rate of return on the assets of each of the banks in both Islamic and conventional banking systems was measured and then the efficient frontier curve was extracted for Islamic and conventional banks. Finally, to apply the CAPM and calculate the systematic risk of banks, the value of bank shares was used for this purpose. Due to the statistical limitations in this field where the necessary data was not available for all 40 investigated banks, and on the other hand it was necessary to use the monthly return rates of these data, therefore subject to the DEA and SFA results, 5 banks from the Islamic banking system and 5 banks from the conventional banking system were selected. Then, according to the data of the monthly stock returns of each of these 10 banks since the second month of 2012 through the end of 2020 with 107 observations, the performance of both banking systems based on the CAPM and estimating the systematic risk rate for each bank was compared. For this purpose, we considered the regression model as Where  is the rate of return for asset i during period t,  is the rate of return for the market portfolio M during t,  (also called excess return) is the difference between estimated return and expected return,  is the beta coefficient and 𝜀 is the error term. To estimate above regression for the selected banks, we used the monthly return rates of the MSCI global index as , since the beginning of 2012 through the end of 2020  and the monthly stock return rates as   for each of the banks. First, this regression was performed for the portfolio of Islamic banks and conventional banks, and then we repeated it for each selected bank, and accordingly, the beta coefficients related to the stock portfolio of conventional and Islamic banks, as well as each of the selected banks, were calculated.

The average efficiency of Islamic banks in data DEA and SFA models was evaluated as 74% and 56.15% respectively, and for conventional banks as 69.5% and 48.13% respectively. By implementing the Markowitz model during the period 2012-2020, the average and standard deviation of Islamic banks' stock returns were calculated as 0.76% and 4.09% respectively, and for conventional banks as 0.68% and 6.35% respectively. Next, by developing ten optimization problems, ten pairs of optimal stock returns and their corresponding risk rates were calculated for each of the two Islamic and conventional banking systems, and accordingly, the efficient frontier curve for each of these two systems was extracted. The average correlation coefficients of stock return rates for two Islamic and conventional banking systems were calculated as 40.4% and 44.1%, respectively, which indicates the  lower amount for the Islamic banking system compared to conventional one. Finally, so as to implement the CAPM for measuring the beta coefficient for Islamic and conventional portfolios, firstly this regression was estimated for the portfolios of Islamic banks and conventional banks. The results are compiled in Table No. (1).

This article aims to assess the efficiency of 15 stock market banks over the period 2014-2022. Utilizing non-parametric radial efficiency (Debreu-Farrell efficiency) and non-radial efficiency (Russell efficiency) methods, we analyze constant, non-increasing, and variable return-to-scale technologies. Recognizing limitations within radial methods, bias-corrected technical efficiency is also estimated using bootstrap data envelopment analysis. Radial analysis reveals inefficiency among all banks except for the Middle East bank. The average Debreu-Farrell efficiency stands at 77% under constant return to scale and 82% under variable return to scale, while the average Russell efficiency is 58% and 67% respectively. These results suggest slack in Debreu-Farrell efficiency. Bootstrap efficiency findings reveal underestimation in both radial and non-radial efficiency, thereby overstating actual efficiency levels. Bias-corrected radial technical efficiency scores from the bootstrap approach indicate inefficiency across all banks, with Dey and Sarmaye banks exhibiting particularly poor performance. Thus, adopting appropriate strategies such as non-performing loan management, increased non-interest incomes, and reduced operational costs is imperative to enhance efficiency.

One of the basic criteria for making decisions in the stock market is stock returns. Stock returns can be affected by risk. Risk is statistically divided into explained (systematic) and unexplained (unsystematic) groups. The present study was conducted with the aim of measuring the efficiency of stock returns based on risk in petrochemical industries by the fuzzy dynamic network data envelopment analysis method. The statistical sample studied are 10 petrochemical companies admitted to the Tehran Stock Exchange. Data analysis was done in two parts. In the first step, systematic and unsystematic risk for entering the network were calculated. In the second stage, using fuzzy dynamic network data coverage analysis, the efficiency of stock returns for petrochemical industries of Tehran Stock Exchange was measured in the period of 2019 to 2019. Based on the obtained results, three petrochemical companies Maron, Jam Petrochemical and Zagros Petrochemical have higher efficiency than other petrochemical companies. Therefore, the three mentioned companies were more controllable for systematic and unsystematic risk among the companies.

Taxation is one of the issues that are considered by various organizations and society and tax avoidance is a kind of use of legal gaps in tax laws to reduce taxes; the purpose of this study is to investigate the factors affecting tax avoidance using a hybrid approach (Metasynthesis). For this purpose, this research in 2022 with a qualitative approach and meta-synthesis tools, has systematically evaluated and analyzed the results and findings of previous research. In this study, a total of 170 articles were extracted and reviewed, and after analyzing the components, 52 articles were finalized. Findings of this study led to the identification of dual dimensions in the form of 30 variables including extra-organizational and extra-organizational factors. Finally, using the Shannon quantitative entropy method, based on the content analysis approach, the effect coefficients of the components identified in the finalized research were determined. Findings showed that the most important indicators affecting corporate tax evasion are concentration of ownership, percentage of dividends and tax reputation; Factors such as inefficiency of labor investment; Social responsibility and the size of the auditing firm have the lowest rank; This means that among the various models and researches studied, less attention has been paid to these issues and their reproducibility.

Reviewing the efficiency of banks as one of the most important pillars of each country's financial markets is one of the essential steps to achieve economic growth and development. Banks, as the most important monetary market entity, have played a very important role in the economy of each country, and measuring the efficiency of banks is of particular importance given their role and the rapid reflection of the policies of this sector in the entire economy of the country. Accordingly, the purpose of this study was to measure the efficiency of selected private banks (modern economy, Pasargadae, capital, exports, nation, trade and welfare) and government (national, export development, industry and mining) during the study period (1393-1395). Be To achieve this goal, two nonparametric approaches (data coverage analysis) and a parametric approach (border production function) have been used using value added and earnings method. The findings confirm the main hypothesis. In the study period, private banks were more efficient than government banks. Regardless of the income approach of the data coverage analysis method, the second hypothesis of the research was that the outcomes of the approaches were similar Parametric and nonparametric is also confirmed.

 The emergence of information technology has led to a huge transformation in the world of business. However, the type and degree of impact of information technology and its different parts onthe efficiency of companies is not known; Efficiency in economics is a broad concept that is used to indicate the state of best possible performance and includes the minimum cost of producing goods or services, the maximum amount of production and the maximum market performance. (ODonnell, 2018). Recently, rapid technological developments have made companies use information technology to ensure their growth in order to survive in the business competition (Fadhilah & Subriadi, 2019).In Iran, the importance of this technology in the field of industry, economy and trade has not been properly clarified for managers and capital owners. Therefore, it is of great importance and necessity to conduct a research that shows the impact of the use of information technology on the efficiency of companies in a documented manner and using data from various companies at different times. Also, information technology has different parts (hardware, software, database, network, human resources) that the use of each sector requires investment and spending the company's limited resources in those sectors. Now, focusing on which part can have a greater effect on efficiency is also an issue that is addressed in the current research. Therefore, the current research tries to address this issue by using econometric models and relying on real data. Therefore, the main goal of the current research is to investigate the effect of information technology on the efficiency of companies admitted to the Tehran Stock Exchange, and based on this, the main and sub-hypotheses of the current research are proposed as follows:Information technology has a significant impact on the efficiency of companies.Investment in hardware, investment in software, investment in database, investment in network and investment in skilled human resources have a significant impact on the efficiency of companies.

 The current research aims to investigate the impact of information technology on improving the efficiency of companies with an analytical-applicative approach. The statistical population of this study includes companies admitted to the Tehran Stock Exchange during the 5-year period from 2014 to 2019. And the research sample is the data of 41 companies that were selected using the systematic elimination sampling method. The variables examined in this research include the dependent of the companys efficiency information technology in five areas:hardwared) Hardware-Invi,(, software (software-Invij), network and communication facilities (Network-Invij), database (Database-Invij)  and investment in skilled human resources  (Humanresources-Invij), company size and risk. The method used in this research (in order to investigate the relationship between independent and dependent variables) is the pooled data model.In order to estimate the model, we first use Limer's F statistic to determine the presence or absence of width from separate origins for each section (using the methods of combined regression patterns and panel data pattern); If the combined regression models are not confirmed, the Hausman test is performed in order to use one of the fixed effects model and the random effects model for estimation. The models investigated in the current research are derived from the model (Fadhila and Sobriadi, 2019).

 The findings of the research indicate that information technology and its components have a positive effect on improving the efficiency of companies admitted to the Tehran Stock Exchange. In this equation, the role of the controlling variable of company size is also confirmed. In fact, information technology can increase the efficiency of companies by investing in five sectors: hardware, software, database, network, and human resources, and this means that companies that have invested more in information technology had a higher efficiency rate.

 that investing in hardware has a positive effect on improving the efficiency of companies. Therefore, it can be said that with the increase in the investment of companies in the hardware sector, the efficiency of the companies accepted in the stock exchange has also increased. Investing in software has a positive effect on improving the efficiency of companies. Based on this finding, it was found that companies can achieve improved efficiency by investing in software and increasing readiness to provide facilities and keep pace with technological developments. Also, investing in the database has a significant effect on improving the efficiency of companies. Based on this, it can be concluded that companies can increase their efficiency by increasing their investment in the database. Investing in the network has a significant effect on improving the efficiency of companies. Networks consist of intranet, extranet and internet. The presence of these networks in the company facilitates the process of exchanging information, carrying out processes and making decisions, and ultimately improves the efficiency of the company. Investing in human resources has a significant effect on improving the efficiency of companies. Therefore, it can be said that companies' investment in human resources can improve the efficiency of companies. Based on the results, the companies were looking for higher efficiency by investing in this sector. Based on the investigations carried out in all the fitted models, it is clear that the company size variable has a positive and significant effect on the efficiency of the companies admitted to the Tehran Stock Exchange  This factor indicates that larger companies, in terms of size, have experienced higher efficiency, and this factor can be caused by the distribution of the fixed cost of these companies on other costs.

This research compares the efficiency of the municipality and the government in collecting tax based on real estate. The indicators used to measure the efficiency, salary and wages per capita, and current cost, are considered as the input and tax collection per capita (for the renovation tax of municipality) is considered as the output. The statistical population of the research includes the Tehran and Isfahan municipalities and the Iranian National Tax Administration of 29 provinces in the country in the years 2011 to 2021. In order to measure the efficiency, the window data coverage analysis approach has been used. The data used in the research estimated by EMS software. The comparison of the efficiency average in the years 2011-2021 showed that the efficiency ratio of Tehran Municipality compared to the Iranian National Tax Administration of Tehran Province is 1.2 and the efficiency ratio of Isfahan Municipality compared to the Iranian National Tax Administration of Isfahan Province is 2.78.

The increase in concentration in the banking sector, along with the problems of the recent financial and economic crises, has shown the importance of banking regulations against the high risk caused by the imbalance in the banks' balance sheets and one of the basic measures in the development of banks is to increase the efficiency of these financial institutions. Therefore, efficiency in banks always has been a matter of attention, and the weakness of the banking system can be a serious threat to the stability of the macro economy. In this way, banks with their credit operations and financing for different economic sectors, they provide suitable conditions for investment and cause the increase and growth of capital and finally the national production. The aim of the current research is to inter temporal relationship between risk, capital and efficiency in Iran's banking system. For this purpose, the data of Iran's commercial and specialized banks have been collected during the years 2006 to 2019 and to evaluate the model, In order to measure the model, the efficiency of banks has been estimated using the stochastic frontier model (SFA), Then, the relationship between risk, efficiency and capital is investigated using the seemingly unrelated regression (SUR) approach. In total, the obtained results show the existence of a relationship between capital and efficiency with risk. The results indicated that with the increase in the capital ratio, the risk of banks decreases and also increasing efficiency increases risk, also with the increase in the internal rate of return of banks, the capital ratio increases and Increasing the size of the bank increases efficiency.

The main goal of this research is to investigate the performance of the Islamic banking system compared to the conventional banking system in terms of efficiency criteria by two parametric and non-parametric approaches. For this purpose, two approaches of data envelopment analysis and stochastic frontier analysis were used. The results of the investigation, in terms of both approaches, indicate that Islamic banks are more efficient than banks operating in the conventional system according to the studied input and output variables. The average efficiency of Islamic banks in DEA and SFA models evaluated as 74 and 56.15 percent, respectively, and for conventional banks as 69.5 and 43.18 percent, respectively. The average efficiency of all banks was 71.8% in DEA and 37.8% in SFA. The results also indicated that Iranian banks performed weaker than other Islamic banks in terms of granting the loans, but better than conventional banks. Also, public banks in Iran perform better than private banks in terms of granting loans. Also, the findings of this research showed that the risk of stock returns related to selected Islamic banks is lower compared to conventional banks, both in terms of systematic risk and unsystematic risk.

Due to the undesirable effects of incentive approaches on the service quality of electricity distribution companies, increasing attention is being paid to the quality aspect of their services in benchmarking models. Although the trade-off between service quality and cost, under the effect of implication of these approaches, does not apply to Iran, but the inclusion of service quality in efficiency analysis is still important theoretically, and also because of the possibility of such a trade-off between scale and service quality in a monopoly structure. This study examines the impact of service quality on the efficiency of Iranian electricity distribution companies, using the duration of interruption as a proxy variable for service quality, and its implication on the need to pay attention to quality in efficiency analysis and benchmarking model. Estimating the efficiency of the mentioned companies using the input-distance function method during 2011-2017 period shows that there is no statistically significant difference between the results of the efficiency analysis, with and without the inclusion of quality of service. Although the results support the pure cost approach to benchmarking, but it is still suggested that the impact of other aspects of service quality of Iranian electricity distribution companies be examined in the efficiency analysis.