“…As emphasized by Kothari (2001), some findings of apparent market inefficiency in existing literature may be artifacts of flaws in methodology. Potential sources of spurious effects include problems in risk measurement (see, e.g., Franks et al, 1991), data issues such as survivorship bias, and the effects of skewness of financial variables (Kothari et al, 2002). This said, there appears to be a set of 'anomalies' (patterns of return predictability) that have so far proven stubbornly hard to explain from an efficient markets perspective, including post-earnings announcement drift, the accruals anomaly, and stock return momentum.…”