In a randomized, controlled trial, the intent-to-treat (ITT) population represents all the study subjects who were randomized to the different treatment groups. It’s the most inclusive group in the study because it ignores people who drop out of the study or who don’t comply with their treatments according to study guidelines. Analysis of the ITT population tends to make two treatments look more similar, while analysis of the per-protocol population tends to emphasize treatment differences. When results are similar for both the intent-to-treat and per-protocol populations, it increases confidence in the study results.
