The STOTT exam has a written and practical portion. The NPCP exam is just written and was designed to validate, preserve, and advance what Jospeh and Clara Pilates created. NPCP sets standards for professional competency to safely and effectively teach the Pilates Method. If you take the time to be STOTT trained, we would recommend that you take the STOTT exam because you learned their method.  NPCP exam would demonstrate proficiency to a wider industry standard and is more classically based.