P-curve accurately rejects evidence for homeopathic ultramolecular dilutions

Homeopathy can offer empirical insights on treatment effects in a null field

OBJECTIVES

A "null field" is a scientific field where there is nothing to discover and where observed associations are thus expected to simply reflect the magnitude of bias. We aimed to characterize a null field using a known example, homeopathy (a pseudoscientific medical approach based on using highly diluted substances), as a prototype.

STUDY DESIGN AND SETTING

We identified 50 randomized placebo-controlled trials of homeopathy interventions from highly cited meta-analyses. The primary outcome variable was the observed effect size in the studies. Variables related to study quality or impact were also extracted.

RESULTS

The mean effect size for homeopathy was 0.36 standard deviations (Hedges' g; 95% confidence interval: 0.21, 0.51) better than placebo, which corresponds to an odds ratio of 1.94 (95% CI: 1.69, 2.23) in favor of homeopathy. 80% of studies had positive effect sizes (favoring homeopathy). Effect size was significantly correlated with citation counts from journals in the directory of open-access journals and CiteWatch. We identified common statistical errors in 25 studies.

CONCLUSION

A null field like homeopathy can exhibit large effect sizes, high rates of favorable results, and high citation impact in the published scientific literature. Null fields may represent a useful negative control for the scientific process.

[Homeopathy-a therapeutic option for medical practice? : An evaluation from the perspective of evidence-based medicine]

Many publications declare homeopathy to be "controversial." However, based on the findings of extensive research on homeopathy, there has long been a broad scientific consensus that there is no reliable evidence of specific medical effectiveness. Overall, the evidence clearly denies effects beyond those of placebo and context. All the more must it be seen as a phenomenon that homeopathy is still the subject of medical and therapeutic practice. This may lie largely in the fact that the homeopathic scene appropriates medical research and the concept of evidence in a way that is suitable to maintain the appearance that there is still a scientifically relevant discourse to dispute. The following article aims to justify that this is not the case, and that homeopathy is, therefore, obsolete as a therapeutic option, even according to the principles of contemporary medical ethics.