Abstract:
This thesis was to study the effect of on quality of disclosure on earning management, before and after improving Accounting Standard of 1999. The sample of the Study were divided into three timing groups : 1996,1999 and 2001 which studied the financial statement data and value of stock exchange of registered companies of Thailand during 1987-2001 from all industrial gruoups except financial group and the sample groups much have complete financial statement. Therefore, only 59 sample were selected. Modified Jones model (1991) was used in finding value from earning management across total accrual to Wilcoxon singed - rank test and to study the effect of negative relationships of earnings management on value relevance of earnings. Multiple Regression Analysis at statistical significance of .05 was used to test earning management relationship with value relevance of earnings. The research results showed that the effect of quality of disclosure before and after improving Accounting Standard of 1999 on earning management, was found of being indifferent with statistical significance. But as regards earnings management, negative relationship with value relevance of earnings with statistical significance found. Thus it could be sumbed up that value relevance of earnings increased while earnings management decreased.