In a recent *JAMA Oncology* Patient Page [1], oncologist H. Jack West and biostatistician Suzanne Dahlberg explain several aspects of cancer clinical trials. I was struck in particular by the description they crafted of p-values:

Statistics Let Us Describe Differences in Outcomes Between GroupsResults for different end points are compared in a few ways to assess whether one strategy is better than another. Differences are considered

statistically significantif the probability of the differences seen occurring by chance, based on mathematical calculations, is below a threshold usually defined as 5%: this is also reflected as a P value of .05 or lower (1.00 representing 100% probability of chance explaining the findings).

If one *must* describe P values in other than scourging terms, this seems to me about as good a job as one could do. Have I overlooked something? It does not escape me how delicate this description is. I note for example how it would collapse with the subtlest change of verb tenseâfrom âoccurringâ to âhaving occurredâ. Also, I appreciate thereâs an awful lot packed into the *deus ex machina* of âbased on mathematical calculations.â But still âŚ wasnât this as good a job as can be done with this thankless task?

**How would you describe P values to a cancer patient advocate who is (as many do) laboring to read the trial literature and make sense of it?**

- West H, Dahlberg S. Clinical Trials, End Points, and StatisticsâMeasuring and Comparing Cancer Treatments in Practice.
*JAMA Oncol*. September 2018. doi:10.1001/jamaoncol.2018.3708