Masicampo E J, Lalande Daniel R
Department of Psychology, Wake Forest University, Winston-Salem, NC 27109, USA.
Q J Exp Psychol (Hove). 2012;65(11):2271-9. doi: 10.1080/17470218.2012.711335. Epub 2012 Aug 2.
In null hypothesis significance testing (NHST), p values are judged relative to an arbitrary threshold for significance (.05). The present work examined whether that standard influences the distribution of p values reported in the psychology literature. We examined a large subset of papers from three highly regarded journals. Distributions of p were found to be similar across the different journals. Moreover, p values were much more common immediately below .05 than would be expected based on the number of p values occurring in other ranges. This prevalence of p values just below the arbitrary criterion for significance was observed in all three journals. We discuss potential sources of this pattern, including publication bias and researcher degrees of freedom.
在零假设显著性检验（NHST）中，p值是相对于一个任意的显著性阈值（.05）来判断的。本研究考察了该标准是否会影响心理学文献中报告的p值分布。我们研究了来自三本备受推崇的期刊的大量论文子集。发现不同期刊的p值分布相似。此外，p值在刚好低于.05时比基于其他范围内出现的p值数量所预期的更为常见。在所有三本期刊中都观察到了刚好低于任意显著性标准的p值的这种普遍情况。我们讨论了这种模式的潜在来源，包括发表偏倚和研究者的自由度。
