The value of a p-valueless paper

Abstract

As is common in current biomedical research, about 85% of original contributions in The American Journal of Gastroenterology in 2004 have reported p-values. However, none are reported in this issue's article by Abraham et al. who, instead, rely exclusively on effect size estimates and associated confidence intervals to summarize their findings. Authors using confidence intervals communicate much more information in a clear and efficient manner than those using p-values. This strategy also prevents readers from drawing erroneous conclusions caused by common misunderstandings about p-values. I outline how standard, two-sided confidence intervals can be used to measure whether two treatments differ or test whether they are clinically equivalent.