{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://publicschema.org/metrics/Period.schema.json",
  "title": "Period",
  "description": "The temporal coverage of a MetricObservation. PublicSchema reifies the period as a separate class (rather than carrying inline start_date / end_date like other Event subtypes) because the SDMX and Data Cube emitters need a single URI-addressable interval to satisfy W3C Data Cube integrity constraint IC-11 (every observation has a value for every dimension, including time). Its end date is the last covered day, so calendar year 2024 runs from 2024-01-01 to 2024-12-31.\n",
  "type": "object",
  "properties": {
    "period_type": {
      "type": "string",
      "enum": [
        "point_in_time",
        "span",
        "cohort",
        "fiscal_year",
        "calendar_year"
      ],
      "$comment": "https://publicschema.org/vocab/period-type",
      "description": "The kind of period: point_in_time, span, cohort, fiscal_year, or calendar_year."
    },
    "start_date": {
      "type": "string",
      "format": "date",
      "description": "The date on which this became effective."
    },
    "end_date": {
      "type": "string",
      "format": "date",
      "description": "The last day on which this is effective. A period includes both its start date and its end date, so a period that applies only on 30 June 2026 has start date 2026-06-30 and end date 2026-06-30."
    },
    "granularity": {
      "type": "string",
      "enum": [
        "year",
        "quarter",
        "month",
        "week",
        "day",
        "hour"
      ],
      "$comment": "https://publicschema.org/vocab/granularity",
      "description": "The granularity of the period: year, quarter, month, week, day, or hour."
    },
    "reference_period_type": {
      "type": "string",
      "description": "An SDMX REF_PERIOD type identifier when relevant (for example, the reference week for labour force surveys, the academic year for school-attendance metrics)."
    },
    "observation_frequency": {
      "type": "string",
      "enum": [
        "A",
        "Q",
        "M",
        "W",
        "D",
        "H"
      ],
      "$comment": "https://publicschema.org/vocab/frequency",
      "description": "The SDMX FREQ code for this period: A (annual), Q (quarterly), M (monthly), W (weekly), D (daily), H (hourly). Carried as a single-letter code; resolves to urn:sdmx:org.sdmx.infomodel.codelist.Codelist=SDMX:CL_FREQ. Named observation_frequency to avoid collision with the benefit-delivery frequency slot in schema/program.yaml.\n"
    }
  }
}