A p-curve analysis confirms: ultramolecular homeopathic remedies are placebos
Researchers tend to report only studies that are positive, while leaving negative trials unpublished. This publication bias can mislead us when looking at the totality of the published data. One solution to this problem is the p-curve. A significant p-value indicates that obtaining the result within the null distribution is improbable. The p-curve is the distribution of statistically significant p-values for a set of studies (ps < .05). Because only true effects are expected to generate right-skewed p-curves – containing more low (.01s) than high (.04s) significant p-values – only right-skewed p-curves are diagnostic of evidential value. By telling us whether we can rule out selective reporting as the sole explanation for a set of findings, p-curve offers a solution to the age-old inferential problems caused by file-drawers of failed studies and analyses. The authors of this article tested the distributions of sets of statistically significant p-values from placebo-controlled