The effect of Financial Statement Comparability on Value Relevance of Earning and Book value with Emphasis on Financial Reporting Opacity and Internal Control Weakness

Introduction
 Value relevance is studied in order to observe the role of accounting information in explaining the return on securities. Accounting information plays an important role when evaluating the future investors of companies in their investment decisions. In accounting studies, the statistical relationship between accounting information and stock prices is used to assess the degree of value relevance of accounting information to shareholders. Value relevance can be considered as the ability of one or more accounting figures to explain changes in returns and prices. Factors affecting the value of accounting information. One of these factors is the accounting comparability.
Comparability is one of the quality-enhancing features of financial reporting that enables users to identify similarities and differences between a set of economic phenomena. The accounting comparability helps users of financial statements to better understand and evaluate the economic performance of a company compared to their peers. Accounting information enables investors to make informed trading decisions and therefore be included in stock prices. However, the usefulness of accounting information for investors depends entirely on the extent to which the information can be modeled on similar companies. The Accounting Standards Board believes that comparability can increase the relevance of accounting information and facilitate investors' evaluation of alternative investment opportunities. More comparability enriches a company's information environment by facilitating benchmarking and giving investors access to a wider range of industry and market information. This means that increasing the supply of information from comparable companies leads to a richer information environment and makes the financial statements of the parent company more informative for capital market participants. Increases the comparability of the quality of information provided in financial statements. Previous studies have shown that comparability improves the accuracy of financial information and makes it easier for market participants to evaluate fairly reported financial statements based on information from similar companies and reduce uncertainty about their accuracy. Ability to compare the cost of collecting and processing company-specific information. Because comparability reduces the cost of collecting and processing investor information, enables accurate and effective evaluation of financial information, increases the value relevance of accounting information.
Also, when there is a financial reporting opacity and a Internal control weakness, the effect of accounting comparability on the value relevance of accounting information is reduced. In the absence of complete transparency in financial reporting, managers are given the opportunity to hide negative information within the company in order to maintain their job and professional reputation. When a company's information environment is opaque, the benefits of comparability of financial statements diminish because investors cannot make a reliable estimate of the numbers reported. Weak internal control weaknesses also cause investors to revise their assessments of the quality and accuracy of existing accounting information. Investors react negatively to the disclosure of internal control deficiencies. Accordingly, ineffective internal financial reporting controls reduce investors' confidence in financial information. Therefore, when internal controls are weak, the advantages of comparability of financial statements are reduced.  The purpose of this study is to investigate the accounting comparability on value relevance of earning and book value due to the role of financial reporting opacity and internal control weakness.
Research Hypothesis:
Hypothesis 1: The accounting comparability has a positive effect on the value relevance of book value per share.
Hypothesis 2: The accounting comparability has a positive effect on the value relevance of earnings per share.
Hypothesis 3: Financial reporting opacity reduces the effect of accounting comparability on the value relevance of book value per share.
Hypothesis 4: Financial reporting opacity reduces the effect of accounting comparability on the value relevance of earnings per share.
Hypothesis 5: Internal control weakness reduces the effect of accounting comparability on the value relevance of book value per share.
Hypothesis 6: Internal control weakness reduces the effect of accounting comparability on the value relevance of earnings per share.
Methods:
 The statistical the population of this study are all companies listed in Tehran Stock Market, in which 102 companies in the period 2013 to 2020 have been selected by systematic elimination method. For data analysis and hypothesis testing, multivariate regression model based on compound data is used
Result:
The results of estimating the research model indicate that the accounting comparability has a positive and significant effect on the value relevance of book value and earnings per share. The findings also showed that when the opacity in financial reporting is high, the effect of accounting comparability on the value relevance of book value and earnings per share decreases. In addition, when there is a weakness in internal controls, the accounting comparability does not have a significant effect on the value relevance of book value and earnings per share.
Discussion and Conclusion:
In general, the findings of this study are consistent with the claim of the Financial Accounting Standards Board that the accounting comparability increases the usefulness of accounting information decision and allows investors to better evaluate investment opportunities.