The Patient-Reported Outcome (PRO) Item That Cost a Trial Its Endpoint Item 4 looked perfect. Durante la última semana, ¿con qué frecuencia el cansancio le impidió realizar sus actividades habituales? Fluent. Natural. The kind of Spanish a reviewer reads once and ticks. Patients answer the item they read, not the one you meant The English said “during the past 7 days”. The Spanish said la última semana. And a patient in Seville filling in a tablet on a Wednesday morning reads la última semana...