فصلنامه پژوهش ها و سیاست های اقتصادی
پیاپی 68 (زمستان 1392)

Some economists believe that monetary policy changes only the nominal variables and has no effect on the real variables. In contrast، some economists believe that under some circumstances monetary policy، in addition to the nominal variables، increases the real variables in the short term and، in some cases، even in the long term. Since 1990s numerous theoretical and empirical studies have been conducted to examine the asymmetric effects of monetary policy on real variables. Some New Keynesian economists believe that monetary policy can produce asymmetric effects on gross domestic product. This paper analyzes the asymmetric effects of monetary policy on gross domestic product in Iran during 1959-2010. We use the RESET tests، Terasvirta (1998)، Terasvirta and Anderson (1992)، Terasvirta (1993)، Nonlinear Smooth Transition Autoregressive and logistic transition function models، and use oil income and private sector investment growth rates as the transition variables with one lag. For estimating the 4-state Smooth Transition Autoregressive Model، we use the non-linear least squares and Genetic Algorithm. We find that the effect of monetary policy on gross domestic product is asymmetric in the studied period. The Multiple Regime Smooth Transition Autoregressive Model reveals 4 different business cycle states in Iran. Monetary coefficients are different in these states and the largest coefficient appears in recessions with declining economy، while the smallest coefficient belongs to booms with decreasing growth rates.

The pivotal role of export in industrialization process has been induced us to study the effect of market structure on export performance of Iranian industries. We use number of firms as a measure of competition to provide an industry-level research. The evidence suggests that competition has a positive and statistically significant effect on export. Therefore، anti-monopolistic policies would help to growth of export and industrialization of Iranian economy.

The purpose of this research is investigation of the privatization process effect on productivity indexes of Listed Companies in Tehran Stock Exchange. Productivity indexes in this research are capital productivity and employee productivity. Sample of research is 42 firms listed in Tehran stock exchange that using the pooled data system and ordinary least square regressions (OLS) model، have been analyzed for the period of 2003-2010. The results show that capital productivity and employee productivity relinquished companies have been promoted after privatization and the amount of privatization have significant positive relation with the capital and employee productivity.

In this paper we study how oil price and oil price volatility affect stock return and volatility of stock return. In order to assess this effect Markov- Switching model has been used and furthermore HP filter، GARCH model and Wavelet analysis model have been used for extracting oil price volatility. Comparison of results shows that Wavelet method has more accurate and detailed results. Furthermore results show that oil price increases do not have significant effect on stock returns and only will decrease of stock return volatility. However oil price volatility in D1 (t) scale that extracting from Wavelet decomposition do not has significant effect on stock return، but oil price volatility in D2 (t) and D3 (t) scales have positive effect on stock return in market boom condition. In addition، results show that، transition matrix is sensitive to scaling on oil price volatility.

In this article we survey money neutrality in long-run according to king - Watson’s method (1997). For this purpose SVAR model with Money stock، Liquidity and GDP data during 1972- 2010 have been used. The results show that the money neutrality and money definition doesn’t have relationship. Changes in the stock of money and liquidity does not affect the production and because the rate of money growth and Liquidity growth rate are zero-order integrated، discussion about long-term relationship would not be reasonable. So in order to increase the production in the economy، we must turn to supply side policies that increases labor productivity and efficiency and increases the production. Results also indicate that at 1% level of confidence، neutrality of long-run money could not be rejected. Under the constraints of short-run money neutrality، similarly the result doesn’t lead us to reject neutrality of long-run money. According to Lucas monetary misinterpretations theory (1972) it should be noted that production response to changes in money stock could be negative. This means that negative monetary shocks could cause that the Lucas long-run aggregate supply curve lose its verticality so negative monetary shocks have real effects in the short run.

In recent years substantial numbers of econometric papers have addressed estimation and inference methods of the Threshold Auto Regression model. Threshold Auto regression model are able to capture asymmetric and nonlinear movement of variables. This paper explains the characteristics of threshold models and some different applications of these models and then، investigates the threshold auto regression models and momentum threshold auto regression models. Finally، presenting some examples of threshold models، we used the threshold co Integration test advanced by Enders and Siklos (2001) to investigate the asymmetric adjustment on long-run (PPP) in Iran between 1339 and 1390. Results prove PPP theory and imply that the adjustment process towards long run PPP is asymmetric.

Providing realistic economic analysis requires that we take into account limitations and complications of human behavior. In this paper، we show that one can''t explain the economic behaviors، only relying on rationality assumption، which is the basis of conventional economic analysis. In conventional economics، the rationality presumption has been defended on numerous grounds. Some claims that rationality-based models are easier to formalize and implement. Others believe that a set of market and non-market factors such as competition، evolution and learning، leads economic decision-makers to a rational behavior. However، in this paper we would show that، a realistic analysis of economic behavior can''t be provided just relying on rationality presumption، and ignoring human behavior limitations. Some economists combine economics and psychology to analyze the behavior of economic institutions. We will discuss the evolution of approaches regarding to this integration and will have a look on latest results in this field. Then، we will explain three basic behavioral limitations، which must be considered in economic analysis: bounded rationality، bounded willpower، and bounded selfishness. Then، as practical evidence، we will mention examples of irrational behaviors in financial markets. These examples indicate that there are numerous cases in which human behavior deviates from conventional models expectations.

According to the political economy literature، a country''s political and economic structures have close، and also complex relationship with each other. Therefore political structure of the country is known to be the leader system of economic management that reflects regime''s economic ideologies. Hence any disorder in the political system، especially in developing countries، could lead to economic instability and disrupts normal flow of the economy which will result in slower economic growth as the most important indicator of economic performance. This study tries to analyze effect of political instability on Iran''s economic growth by using political and social Time Series data during period 1339-1388. For this purpose، effect of political instability on economic growth based on formal political instability and informal political instability indexes has been tested by using APARCH technique. Empirical findings of this study indicate that variables related to the both mentioned indexes have a negative effect on economic growth