# Method

## Sources
- Podcast Index feed dump, table `podcasts`, 4,711,475 rows, dated 2026-08-16.
  Reference timestamp 1786838400 (2026-08-16 00:00 UTC).
- Apple Podcasts "Top Shows" top-100 for 18 storefronts (us, gb, ca, au, de,
  fr, es, it, nl, se, br, mx, jp, in, ie, nz, pl, kr), fetched 2026-09-06,
  HTTP 200 and 100 results for every storefront.

## Join
1,800 chart slots hold 1,479 distinct itunesIds; a show that charts in several
storefronts is counted once. 1,387 of those ids match a row in the dump on
`itunesId`. Every share of the charts in this dataset is a share of those 1,387
shows, pooled across the 18 storefronts.

## Host normalisation
`host` in the dump is a registrable domain. It is lowercased and a small alias
map merges domains belonging to one company (tools/count.py, HOST_ALIASES):
spotify.com, spotify.link, podcasters.spotify.com and creators.spotify.com to
anchor.fm; feeds.buzzsprout.com to buzzsprout.com; libsynpro.com and libsyn.org
to libsyn.com; podbean.eu to podbean.com; omnycontent.com to omny.fm;
megaphone.link and feeds.megaphone.fm to megaphone.fm; simplecast.fm to
simplecast.com; and the feeds.* forms of soundcloud, captivate, redcircle,
acast, transistor and fireside to their bare domains. Anchor prints as
"Anchor (Spotify for Creators)". Display names in the report and hosts.csv map
to these domains: Prisa Audio = prisasd.com, Pod.space = pod.space, Audiomeans =
audiomeans.fr, Podigee = podigee.io, ART19 = art19.com, Omny Studio = omny.fm,
RSS.com = rss.com, Podomatic = podomatic.com, FeedBurner = feedburner.com. The
full map is DISPLAY in tools/report_anchor_facts.py.

## Definitions
- active: newestItemPubdate falls within the 90 days before 2026-08-16. Feeds
  with no newest-episode date are never active but stay in every denominator.
- start year / oldest_year: the year of oldestItemPubdate.
- enterprise hosts: Megaphone, Omny Studio, Acast, Simplecast, Audioboom,
  ART19, Podigee, Audiomeans, Prisa Audio.
- creator hosts: Anchor (Spotify for Creators), Buzzsprout, Spreaker, RSS.com,
  Podbean, Libsyn, Transistor, Captivate, Castbox, SoundCloud, iVoox.
  The two lists are fixed and do not cover every host, so they do not sum
  to 100%.

## Caveats
- episodeCount is capped at 1,000 for recently refreshed feeds, so any median
  or sum at or near 1,000 is a floor.
- episodeCount is unreliable for Buzzsprout in this dump; no Buzzsprout episode
  figure is published and its median prints "n/a".
- The start year is the year of the oldest episode still in the feed, not the
  year the show launched. Feeds that drop old episodes read as younger than
  they are.
- A storefront is Apple's store, not the show's country of origin. A US show
  charting in Ireland counts in the ie row.
- The dump is dated 2026-08-16 and the charts 2026-09-06, three weeks apart. A
  show that charted on 2026-09-06 but entered the index after 2026-08-16 cannot
  join.
- All chart shares are shares of the 1,387 joined shows, not of 1,479 chart ids
  or of 1,800 slots.

Data: CC BY 4.0, Podcastquery, September 2026