# Reference

Quick lookups that support the rest of the manual.

## Trial statuses

Draft
: Being built in the setup wizard; not visible to participants.

Recruiting
: Live and accepting participants.

Not recruiting (recruitment closed)
: Live but no longer accepting participants, either the completion target was reached
  (permanent) or the enrolment limit paused it (may resume).

Completed
: Finished.

## Participant statuses

| Status | Meaning | Counts toward enrolment limit? | Counts toward completion target? |
| --- | --- | --- | --- |
| Registered / waiting to unlock | Signed up, not yet started | Yes | No |
| Active | Currently taking part | Yes | No |
| Completed | Finished the trial | Yes | Yes |
| Withdrawn | Left or removed | No (frees a place) | No |

## Assessment timings

| Timing | When it is asked |
| --- | --- |
| At enrolment | Eligibility screening |
| Before treatment | Baseline measures |
| Start of each treatment period | At the start of each intervention phase |
| End of each treatment period | At the end of each intervention phase |
| Before each daily session | Before a listening session |
| After each daily session | After a listening session |
| Every day | A daily check-in |
| End of trial | The final questionnaire |

## Arm types

| Type | Listening | Purpose |
| --- | --- | --- |
| Active | Therapeutic sound | The intervention under test |
| Sham | Control sound | Blinded comparison, paired to an active arm |
| Washout (nothing) | None | A rest period with no listening |
| Washout (unmodulated) | Plain sound | A rest period with non-therapeutic listening |

## Recruitment terms

| Term | Definition |
| --- | --- |
| Participants to complete (per arm) | Soft goal of completers for an arm; sets its randomisation share |
| Estimated completion rate | Fraction expected to finish (0 to 1) |
| Total completion target | Sum of per-arm targets; the irreversible stop |
| Total enrolment limit | Total completion target ÷ rate, rounded up; the reversible pause |

## Architecture diagrams

The `tinnitus-api` repository holds architecture diagrams under `docs/architecture/`
(participant journey, trial-setup journey, data model, audio-assignment decision, and
more). These can be embedded here as the manual grows; they are the authoritative
picture of how the system fits together.