Two recent randomized controlled trials (RCT) on online hemodiafiltration (HDF) did not show a treatment effect on patient survival when compared with low‐ or high‐flux hemodialysis. Interestingly, post‐hoc (on treatment) analyses from both trials unequivocally showed reduced mortality in the patient group achieving the highest convection volumes. Moreover, a third trial recently found a significant 30% decrease in mortality when HDF was applied with a mean convection volume of 23.7 L per session, which was somewhat higher than the average volumes reached in the aforementioned trials. Altogether, these findings support the concept of a dose-response effect, in which a minimally delivered convection volume is required in order to show a survival benefit.