Placebo Tests of Conditional Conservatism
研究发现Basu（1997）提出的条件保守主义度量存在向上偏误，即使修正后的度量仍存在类似问题，建议谨慎使用该不对称及时性模型，并展示了安慰剂检验在档案研究中的价值。
ABSTRACT Basu (1997) proposes a measure of financial reporting conservatism based on asymmetry in the conditional earnings/returns relation. Patatoukas and Thomas (2011) show upward bias in this measure, because a placebo—lagged earnings—also exhibits similar asymmetry. Ball, Kothari, and Nikolaev (2013a) and Collins, Hribar, and Tian (2014) propose alternative explanations for the bias and offer revised measures to overcome the bias. However, we find that both revised measures remain substantially upward-biased. In particular, a placebo based on lagged share price mimics time-series and cross-sectional variation observed for the revised measures. More generally, we find biases in the asymmetric timeliness specification because earnings, accruals, and other measures of performance are often related to second and higher moments of the distribution of returns. In addition to suggesting that the asymmetric timeliness specification be used with caution, our study illustrates the useful role placebos can play in archival studies. Data Availability: Data are available from the sources identified in the text.