[Intention-to-treat]. 
What is meant by intention-to-treat?  Why should data be analyzed in controlled trials in a way that all participants are included in the group to which they were randomly assigned, regardless of whether they completed the intervention given to the group?  In this Tutorial, the logic of the intention-to-treat principle is outlined.  It is shown that study results may be biased by excluding patients post hoc thus producing spurious effects that do not exist in the population under study.  The intention-to-treat strategy avoids this bias.