New Guidelines for Statistical Reporting in the Journal

Some Journal readers may have noticed more parsimonious reporting of P values in our research articles over the past year. For example, in November 2018, we published two reports from the Vitamin D and Omega-3 Trial (VITAL), 1,2 a two-by-two factorial, placebo-controlled, randomized trial assessing whether vitamin D or marine n−3 (also known as omega-3) fatty acids prevent cardiovascular disease or cancer. For the n−3 portion of the trial, Manson et al. 2 reported 2 prespecified primary outcomes and 22 prespecified and other secondary outcomes — not uncommon in large, expensive randomized or observational studies. The n−3 fatty acids did not significantly . . .