4.2 Tesing for value relevance
Our approach in this section included testing whether the relation between earnings per share and the book value of equity per share with stock prices varies between local accounting principles and IFRS.Our value relevance metric is based on the explanatory power of a regression of stock prices on net income and the book value of equity.In order to obtain a measure of stock price that is unaffected by mean differences across industries (which would affect the comparisons of explanatory power) we applied the methodology proposed by Barth et al.(2008) and regressed stock price P on industry fixed effects.The next step was to model the residuals from the previous step P* as the dependent variable on book value of equity per share(BVPS) and net income per share (NIPS) separately for the pre and post-IFRS periods.In order to ensure that accounting information has been fully disclosed to the market we followed Lang et al(2006,2003) and estimated P six months after the fiscal year end. In the next model and all the following.we have pooled both mandatory and voluntary IFRS adopters in order to control for incremental differences between the two groups of firms,so as to extract more salient inferences regarding the impact of IFRS on accounting quality (Byard,Li&yU,2011).The general form of the regression model is as follows: