فصلنامه دانش حسابداری
پیاپی 5 (تابستان 1390)

The stock market is one of the most attractive investment choice from which a large amount of profit can be earned. This study presents a PSO-based methodology to deal with Stock market index prediction. The study showed superiority in applicability of the proposed approach by using Tehran Stock Exchange Index (TSEI) and comparing the outcomes with conventional method such as Simple Exponential Smoothing (SES), Hoelt-Winters Exponential Smoothing (HWES), Auto Regressive (AR), Moving Average (MA), Auto Regressive Integrated Moving Average (ARIMA). Experimental results clearly showed that PSO approach meaningfully outperforms all of the conventional method in terms of MAD, MSE, RMSE and MAPE. Additionally, evaluation statistics of the proposed approach significantly decrees variance of the errors compared to the conventional method.

This research investigates the relationship between quality of earnings and future stock returns in the selected firms totally, and in the firms in separate categories with various degrees of earnings quality, by choosing the accruals as the representative of earnings quality for the firms listed in the Tehran Stock Exchange (TSE). In this study the size and growth of firms are taken as the control variables. In hypothesis testing, the accruals and their components in arbitrary and non-arbitrary values are used as independent variables, and the future stock returns are taken as dependent.Using data from 91 firms in period 1375-1386, and the method of regression with cross-section series data, the results indicate that in the totally assessment, except for some cases in the medium and low degrees of earnings quality, the future stock returns are not affected by the earnings quality. Accruals components were also examined for which similar results were found. When the firms were categorized into three segments based on the degree of earnings quality, separate hypothesis tests indicate significant relationship between future stock returns and earnings quality.

The purpose of this paper is to provide a theoretical framework to explain and predict accounting reforms in Iran, using the contingency international model explained by Lüder (version 2001). This model is used by many researchers to explain the process of system innovation in several countries. Survey findings indicate that governmental accounting in Iran is on the verge of a fundamental transformation. Increasing demand for more information, the search proposed reforms of the public sector, including legal requirements, concerning operational budget, is the primary driver of such a transformation. Also, the model, when applied to predicting the future trend of the reforms in Iran, confirms the predictive power of Lüder’s innovation.

Corporate governance is a set of policies, methods and proceedings that are carried out to provide the required interests of firm’s stockholders and accountability, transparency and fairness in firm’s operation, using internal and external mechanisms. There are two contrary views expressed in the literature, regarding the relationship between corporate governance and audit function. First, corporate governance as a set of internal and external controls may reduce misreporting risk and damaging manipulation that, in turn, improves auditing process and effectiveness, and then, makes audit fees to reduce. Second, improved governance creates needs to auditing function that could raise audit fees. This study examines whether corporate governance mechanisms correlate with audit fees in Iran or not, and such a correlation moves upward or downward. We use a sample of 201 firms listed in Tehran Security Exchange (TSE) in 2008, and select 10 known factors of corporate governance from the relevant theories and sorces, and analyze the expected relationship between corporate governance and audit fees. The results show that two factors of corporate governance, namely the share owned by government institutions and the type of auditor are correlated with audit fees significantly and directly.

This paper investigates stock valuation in Tehran Stock Exchange with regard to behavioral heterogeneity and bounded rational behavior of agents. The related information of the fundamental factors are disseminated and become available for the public, and investors assess the stock with different models, for example Gordon model. However, because of different expectations of investors, the amount of deviation from the fundamental value and the lengthiness of this deviation are viewed important. In this study, behavior of two groups of investors is examined. First, the fundamentalists who believe in movement of stock prices toward the fundamental value. Second, the chartists who think stock prices should be different from the fundamental value. Results by monthly data show that investors switch between different strategies and sometimes the chartists force the fundamentalists to change their strategies and coexist with them.

Audit partner's expert view is based on the files created by audit team as well as auditors’ performances. Quality reducing behavior of auditing, which is the result of auditors’ practice during audit period, could be viewed important since it reduces the effectiveness of collected evidence that at the end creates bias in the partners’ view. This research is descriptive-survey study and the theoretical issues are library based. The research administrates a questionnaire for data collection and hypotheses testing, using Pearson correlation. In this research the statistical population includes senior executive auditors who are working at the private audit firms in Iran. The results show that quality reducing behavior of professional auditing is not affected by auditors’ perception of psychological contract breach or fulfillment or organizational affective commitments. However, there is a significant relationship between auditors’ perception of psychological contract breach or fulfillment and affective commitments in one hand and quality reducing behavior of non-professional auditing in the other hand that jeopardizes audit quality by reducing coalescence, efficiency and effectiveness of audit firms indirectly.

The purpose of this study is to investigate the relationship between operating cash flows and dividend changes. This is applied to the impact of operating cash flows on the lagged dividends and the net operating income. The statistical population was taken from listed companies in Tehran Stock Exckange, TSE, and a sample of 136 listed companies was surveyed. Despite the importance of operating cash flows in evaluating the cash dividend policies, the results showed no significant relationship between them. In order to re-examine the impact of operating cash flows on cash dividend policies, the sample is divided into three sub-samples with regard to growth level values. Again there were no significant relationship between dividend changes and operating cash flows of companies. This shows that there may be some other factors that create changes in the cash dividend policies.