Indication of Measures of Uncertainty for Statistical Significance in Abstracts of Published Oncology Trials

Key Points Question Do the abstracts of oncology randomized clinical trials with results of marginal statistical significance express uncertainty, and what characteristics are associated with uncertainty expression? Findings This systematic review and meta-analysis of 556 phase 3 randomized clinical trials found that most of the abstracts do not fully express uncertainty, and that uncertainty expression decreases when the P value surrounding a result is below its prespecified α level. The expression of uncertainty appears to be increasing over time. Meaning It appears that a P value below the prespecified α level is often treated as a discrete threshold for statistical significance in publication of randomized clinical trials.