'Treatment Days' on Efforia mark the duration of active treatment within a protocol. 'Treatment Day 1' is the first day a participant starts a specific treatment in the protocol.

These Treatment Days allow both authors and the Efforia system to schedule related tasks based on when a participant actually starts the treatment. This is different from 'Protocol Days,' which are counted from the day a participant joins a protocol, not necessarily when they start a treatment.

Authors use 'Treatment Days' for scheduling tasks directly related to the treatment—like taking medication or performing specific exercises. On the other hand, 'Protocol Days' are used for overall timeline management, which includes introductory activities, baseline measurements.

The reason 'Treatment Day 1' might not coincide with 'Protocol Day 1' is that a protocol often includes initial tasks like baseline measurements or even waiting periods for product shipments before the treatment officially begins.

Remember, 'Treatment Days' keep track of progress within the active treatment phase, while 'Protocol Days' chart the entire journey through the protocol.