Dispatch Queue Depth

Definition

Dispatch Queue Depth (DQD) is the instantaneous count of response tickets in an open state within the CHLORA dispatch queue. A ticket is open from creation — whether raised automatically by a metric breach, a sensor fault, or manually by an operator — until it reaches a terminal state of RESOLVED, CLOSED, or CANCELLED. Tickets in ACKNOWLEDGED or IN_PROGRESS remain counted; only terminal tickets leave the queue.

Why it matters

DQD is the facility's real-time measure of whether response capacity is keeping pace with incident generation. A queue that grows faster than crews clear it signals that crews are saturated, that a fault is fanning out across many units, or that an upstream metric is flapping and spamming tickets. Because it samples every minute, DQD is the earliest dashboard warning of an operational pile-up and feeds directly into the crew-staffing model and the Operations Dashboard health banner.

Formula

DQD is a direct count of open queue entries, partitioned by severity for escalation logic:

DQD(t) = | { tickets : state ∉ {RESOLVED, CLOSED, CANCELLED} } |

Severity partition (informational, not summed differently):
  DQD = n_P1 + n_P2 + n_P3 + n_P4
  P1 = life-safety / containment      (always escalated)
  P2 = specimen-at-risk
  P3 = degraded service
  P4 = routine / advisory

Aging guard:
  if any single ticket open > 4 h            → auto-escalate one band
  if DQD > warn AND d(DQD)/dt > 0 for 5 min  → BACKLOG_GROWING flag

Sampled and committed once per minute; no smoothing applied.

Inputs

Units & Scale

DQD is a non-negative integer count of tickets. It is additive across dispatch zones — facility DQD is the sum of per-zone open counts. It is never averaged over time for alarming (the instant value drives thresholds), though a 60-minute moving average is published alongside it for trend context. Precision is one ticket. A staleness flag is raised if the queue heartbeat is missed for more than 3 minutes.

Sampling & Source

• Counted every 1 minute by CHLORA from the live dispatch queue.
• Inflow is event-driven from metric breaches, PhytoSense Mesh faults, and operator action.
• The instantaneous count drives thresholds; a 60-min moving average is shown for trend only.
• Stale handling: queue heartbeat missed > 3 min → last value held, marked STALE, and a self-diagnostic ticket raised.

Thresholds

Recent Trend

Facility open-ticket count, last 14 one-minute samples:

Interpretation Guidance

Related Metrics

Related SOPs

• SOP Library — dispatch, triage, and surge-staffing procedures.
• Backlog surge response & incident-commander stand-up on CRIT — see the SOP Library.
• Alarm escalation & ticket de-duplication — Monitoring Systems.