In Brief: Statistics in Brief: Confidence Intervals: What is the Real Result in the Target Population?

Excerpt

Authors of a recent article [1] indicated there was a difference (p = 0.015) in compliance at 6 months between the percentage of patients with osteoarthritis receiving insoles (71%; 32 of 45) versus the patients receiving braces (45%; 21 of 46). The small p value along with randomization of the patients provided strong evidence that the percent compliance in the target population (ie, all patients with osteoarthritis being treated by these methods) really is different. However, the p value alone does not provide us with much information concerning the magnitude of the difference in compliance in the target population. For that, we need to consider the estimated difference of 26% (71%–45%) and appropriate confidence interval. …