MeridianMERIDIAN

Periodicity

datetime.component.periodicity

Frequency or recurrence label. Used in scheduling, reporting cadence, and time-series metadata.

Casts to
VARCHAR
Scope
broad_words

Background

Origin

FineType defines periodicity itself, as a frequency or recurrence label used in scheduling, reporting cadence and time-series metadata.[1] FineType's definition accepts eight words: Once, Daily, Weekly, Biweekly, Monthly, Quarterly, Yearly and Never.[1]

Two published vocabularies for frequency sit close to these words. (Meridian's view) SDMX publishes a code list for the concept of frequency, CL_FREQ, whose values indicate how often data are produced, for example weekly, monthly or quarterly.[2] The SDMX frequency code list notes that frequency may refer to different stages of production, so a series could be disseminated annually while its underlying data are compiled monthly.[2] RFC 5545 allows FREQ to take the values SECONDLY, MINUTELY, HOURLY, DAILY, WEEKLY, MONTHLY and YEARLY.[3] RFC 5545 expresses multiples through a separate INTERVAL rule part, where a value of 8 within a DAILY rule means every eight days.[3]

Use

Wiktionary gives biweekly two senses, occurring once every two weeks and occurring twice a week.[4] When a column says Biweekly, find out from the data's documentation or from the gaps between its dates which of the two it means before you schedule or aggregate on it. (Meridian's view)

The FRED API lists Semiannual among its frequencies, alongside weekly frequencies named for the day the week ends, such as Weekly, Ending Friday.[5] Expect labels outside a short list, and spellings such as Annual for Yearly, and map them to one vocabulary of your own rather than rejecting the rows. (Meridian's view) Treat a periodicity label as metadata about a series, and check it against the series' actual dates, since a declared cadence and the delivered one can differ. (Meridian's view)

Where you'll meet it

The Federal Reserve Bank of St. Louis's FRED API returns each series with a frequency field, such as Annual for the GNPCA series, beside a short code such as A.[6]

Sources

  1. [1]finetype/labels/definitions_datetime.yamlFineType
  2. [2]Code list for concept "Frequency"standard
  3. [3]RFC 5545 - Internet Calendaring and Scheduling Core Object Specification (iCalendar)standard
  4. [4]biweekly - Wiktionary, the free dictionarysecondary source
  5. [5]St. Louis Fed Web Services: fred/series/observationsdocumentation
  6. [6]St. Louis Fed Web Services: fred/seriesorganisation

Use it

CLI · DuckDB
$ finetype infer -i "Daily" --mode column
→ datetime.component.periodicity

SELECT ft_infer('Daily');
-- → 'datetime.component.periodicity'
Cast expression
{col}

Schema

https://meridian.online/schemas/datetime.component.periodicity · Frictionless type string

finetype taxonomy datetime.component.periodicity -o json-schema

Type Registry