Editor-in-Chief Alan Jette, PT, PhD, FAPTA, talks with Kathleen Mangione, PT, PhD, FAPTA, about something critically important to physical therapists but rarely top of mind: treatment fidelity. Was the treatment given in a trial actually delivered as intended? Did the patients perform the techniques correctly? Did the patients get winded or fatigued, which would suggest they understood intensity? And how well did the patients do the exercises in real-life settings, indicating that they applied what they learned in sessions?