Regarding the economic environment, firms may adopt IAS because they anticipate IAS will become mandatory in the near future. If this is the case but application of IAS is not associated with an improvement in accounting quality, then our tests are biased against finding that IAS-based accounting amounts are of higher quality. Also, Land and Lang [2002] show that accounting quality is improving worldwide. Therefore, any improvement in accounting quality we observe after firms adopt IAS could be obtained even if firms do not adopt IAS. Section 3 discusses the research design features we incorporate to mitigate the effects on our accounting quality comparisons arising from changing incentives and other temporal economic changes.