Uncertain use of a fixed p value significance threshold in randomized clinical trials.

The continued use of a fixed p value significance threshold, such as p < 0.05, in randomized clinical trials has long been debated. Although such thresholds are conventional, they may not always align with the ethical principle of beneficence, which emphasizes minimizing harm and maximizing benefit. Reliance on a single, fixed α level increases the risk of both false-positive (type I) and false-negative (type II) error rates, thereby either exposing patients to ineffective or harmful treatments or withholding beneficial therapies. While lowering the threshold to values like 0.005 may reduce the false-positive rate, it also increases the false-negative rate and does not resolve the reproducibility crisis. Similar to diagnostic testing, the selection of a significance threshold should be context-dependent, influenced by study design, sample size, prior evidence, and effect size, among other things. Employing a flexible α level that balances type I and type II errors may enhance both scientific validity and ethical integrity. Thus, rigid adherence to fixed α levels, no matter how stringent, may be methodologically limiting and ethically questionable.