{
  "slug": "interarrival-time",
  "term": "Interarrival time",
  "aliases": [
    "Inter-event time"
  ],
  "definition": "An interarrival time is the elapsed interval between consecutive events in a specified event stream.",
  "note": "Choose the stream before computing gaps: all replacements in a fleet and replacements of a single device are different observations. The homogeneous Poisson model assumes independent, identically distributed exponential gaps; a mean gap alone does not establish that model. Event count per calendar window and gap duration are different variables.",
  "related": [
    "rate-of-occurrence-of-failures",
    "annual-replacement-rate",
    "hazard-rate"
  ],
  "citations": [
    {
      "id": "nist-hpp",
      "title": "NIST e-Handbook 8.1.7.1: Homogeneous Poisson Process",
      "url": "https://www.itl.nist.gov/div898/handbook/apr/section1/apr171.htm",
      "accessed": "2026-10-12"
    },
    {
      "id": "hesela-measurement-clocks",
      "title": "Hesela: Disk replacement rates are not disk lifetimes",
      "url": "https://hesela.com/analyses/mttf-vs-field-replacement-rates/",
      "accessed": "2026-10-12"
    }
  ],
  "status": "shipping",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-12"
}