فصلنامه بررسی های حسابداری و حسابرسی
پیاپی 58 (زمستان 1388)

In this research, the reliability qualitative characteristic as a measure for assessing the earning quality of listed Tehran Stock Exchange companies has been studied. To study the subject, Three hypotheses were formulated which showed the market's response to the reliability qualitative characteristic and measures such as accruals quality, conservatism and Working capital accruals abnormal were used for operating the reliability qualitative characteristic. In the first hypothesis, Earning Response Coefficient (ERC) and two hypothesis R2 (the explanatory power of earning) were compared in two portfolios formed based on the reliability qualitative characteristic and in the three hypotheses, the relationship between the cost of capital and the reliability qualitative characteristic was studied. In order to do the studies, 90 listed Tehran Stock Exchange companies during the 1998-2007 period were chosen and the relevant tests were done through multi-variable and simple regression models by a cross-sectional method for an average period of 10 years. Obtained results showed that ERC portfolio of companies with high reliability was more than that of those with low reliability qualitative characteristic and also were not between relationship cost of capital and the reliability qualitative characteristic.

In each organization, manager is the responsible of internal control system. One of the most important internal controls that use it forerunner countries and big companies is internal audit. Internal audit can have special effects to supply the user's needs of its operation results. One of the most important users of internal audit operation results are external auditors. If external auditors know audit department and its usefulnes's and decide to rely on their operation results, different aspects of external audit function will be affected, one of them is audit plan that includes different parts. This research by using analytical-descriptive approach aims to appoint kind of changes and their causes. This research results show that external auditors rely on internal auditors and their reliance causes lowering time and cost budgets in audit plan.

This essay deals with the possibility of better description of market return covariance and the efficiency of share company which are listed in Tehran stock exchange and seven world countries’ as well as capital asset pricing model by using wavelet conversion approach. In this sense, data was extracted that related to the securities and stock exchange indices of Tehran, Seoul, Hong Kong, Buenos Aires, Mexico City, Vienna, London, New York, NASDAQ, and international indices of New York, S&P100, S&P500 indicators and their components as well as details which derived by different levels of Haar, Daubechie, Symlet, Coiflet. The results indicated that Betas extracted by using wavelet, are meaningfully higher than this status, and from the other hand, the efficiency of different functions applied in wavelet conversion is identical, but the higher level that identifies the longer time scale, are more meaningful and efficient. The efficiency of time application with different is not the same for various indices, and different markets present the efficiency within better and different time scales.

In this paper, we examine relation between accounting losses and accounting conservatism over a 7- period in 48 loss firms in Tehran Stock Exchange. We report evidence that accounting conservatism and firm size have a positive relation and financial leverage has a negative relation with accounting losses. there is no relation between accounting losses and governmental ownership in study sample. Our findings contribute to the literature on accounting conservatism and they implicate that conservatism is likely to be an efficient financial reporting mechanism to increase firm value in a long term period because it restrict opportunistic payment to managers and other contracting parties. The increased firm value is shared among all parties to the firm increasing everyone’s welfare. In that sense, conservatism is an efficient contracting mechanism.

In this research has been examined the relationship between liquidity market changes (i.e. bid-ask spread and depth) as a proxy of information asymmetry around quarterly earning announcements and the percentage of independent directors of board, ownership percentage of institutional investors and internal auditing as corporate governance mechanisms in the firms listed in Tehran stock exchange from 1383-1386 (2005-2008). For examine relationships are utilized Pearson correlation test and Mann-Whitney test for internal auditing hypotheses and spearman correlation test and Kendall’s Tau-b test for percentage of independent directors of board and institutional investors hypotheses. Results indicate that there isn’t meaningful relationship between internal auditing and percentage of independent directors of board and information asymmetry. While, information asymmetry has meaningful relationship with institutional investors. Also via comparison changes of bid-ask spread before and after earning announcements by Wilcoxon test is concluded that level of information asymmetry after announcement is more than before it and this subject is consistent with previous researches.

The article set out to create useful predicting tool for pricing initial public offerings through combining neural networks and genetic algorithm. The theoretical framework of this study is information asymmetry theory. Although the literature of pricing initial public offerings introduces variety of possible signals, a few of them have considerable effect on efficiency of predicting. The results show that combining neural networks and genetic algorithm in order to selecting the best variables improves considerably the forecasting power.

This research compares regression analysis including time series regression, cross section regression, mean regression and pooled regression for accounting data. With limited accounting data and statistical measure like R square, F test and T test, the comparison of regression analysis, is done. The results reveal that time series regression is useful in case studies and cross section regression is useful in annual studies and pooled regression is useful in comprehensive studies. Pooled regression frequently is used in accounting studies because it prepares comprehensive result without bias. Mean regression isn’t used in recent accounting studies because it focus on central data