本文檢視Basu (1997)盈餘不對稱及時性觀念下，盈餘落後反應對穩健性比較之影響。根據盈餘之落後反應、盈餘之不對稱反應以及兩者交互作用之結果，我們預期盈餘的不對稱及時性不僅存在好壞消息發生之當期，亦存在短暫的落後期間，因此以盈餘報酬間關係作為比較公司間穩健性之指標時，須同時考慮當期及累積期之不對稱性大小，亦須同時考慮盈餘落後反應之期間長短。本文以盈餘多期反應模型捕捉盈餘對好壞消息之落後多期反應，預期盈餘的不對稱及時性在當期及落後較短期間為正，在盈餘落後期間拉長、壞消息對盈餘的影響完全反應完後會轉為負。本文以美國74,550 筆公司- 年之樣本檢視上述預期，而實證結果均與預期相符。

This paper examines the effect of earnings lags on estimating and comparing the extent of conservatism based on Basu’s (1997) asymmetric timeliness concept. Based on earnings lags and earnings asymmetry, as well as the interaction between these two; we assert that any comparisons of the extent of conservatism should take the magnitude of both concurrent and cumulative asymmetric timeliness into consideration. The length of recognition lag should also be considered. In the present study, we construct a multi-period model to capture lags in earnings response to good news, as well as to bad news. We predict that positive asymmetric timeliness exists in the current period and with short lags. We also predict that asymmetric timeliness turns negative as lags increase. Using a sample of 74,550 U.S. non-financial and non-utility firm-years, empirical results are consistent with our predictions. Results are also robust to several changes in model and sample specifications.