Prostate-specific antigen velocity (PSAV) is one of the oldest concepts in PSA screening, yet today it is one of the most controversial. Publication of a wide range of studies with different designs, study populations, and results has fueled uncertainty about the best way to use PSAV and confused the issue of its utility in the early detection setting. Studies of disease prognosis suggest that PSAV is strongly associated with lethal cancers. However, prospective screening trials find that PSAV is at best a weak predictor of high-risk disease. In this commentary, we synthesize and reconcile the evidence about the value of PSAV in the early detection setting. We review recent studies of PSAV and determine a set of statistical considerations that we believe to be critical in study evaluation and interpretation. We explain why the association between PSAV and disease-specific survival does not necessarily imply that PSAV will be a useful screening tool. In addition, we argue that the standard concept of PSAV--the absolute change in PSA per year--confuses disease aggressiveness with the interval from disease onset to detection. We therefore recommend that other methods be explored to incorporate information about PSA kinetics that could ultimately improve--and even transform--how we detect and treat prostate cancer.