# Where the vocabulary lives, and what makes a term catch on

Grouped by section, the field Schema.org itself publishes, health is the largest extension field and the least used, 75.00% of its terms under a thousand websites. Grouped by how many types a property attaches to, adoption climbs without exception, from 52.56% down to zero.

> Source: https://eduarddziak.com/structured-data/what-gets-used/
> Snapshot: July 2026
> Updated: 2026-08-19
> Data: /data/schema-stats.json and /data/explorer.json
> Licence: Apache 2.0, credit requested

## Summary

| Measure | Value |
| --- | --- |
| Real terms | 2,487 |
| Health section, under 1,000 websites | 75.00% |
| Properties | 1,529 |
| Attached to 1 type, under 1,000 websites | 52.56% |
| Snapshot | July 2026 |

## Key findings

- Health is Schema.org's largest extension, 280 terms, and 75.00% of them sit on fewer than 1,000 websites.
- Core holds 1570 terms, and 35.03% of those sit below 1,000 websites.
- Properties attached to one type sit below 1,000 websites 52.56% of the time.
- Not one of the 3 properties attached to ten or more types goes that unused.
- Adoption rises at every step up in breadth, across all four groups, without an exception.

## 75.00% of health terms sit on fewer than 1,000 websites

Below I group all 2,487 real terms by section, with the share of the section sitting on fewer than 1,000 websites.

| Section | Terms | In the bottom band |
| --- | --- | --- |
| Core | 1570 | 35.03% |
| Pending | 569 | 62.74% |
| Health | 280 | 75.00% |
| Bibliographic | 25 | 76.00% |
| Automotive | 24 | 37.50% |
| Attic | 12 | 83.33% |
| Machinery | 6 | 83.33% |
| Unpublished | 1 | 100.00% |

All sections together, 1,161 terms in the bottom band out of 2,487.

A section is the field Schema.org publishes to say where a term lives. Core holds far more terms than any other, 1570 of them, and 35.03% sit in Google's smallest band. Health is the largest of the five named extensions, at 280 terms, and more than double core's share of it goes almost unused. I expected the extensions to trail core. I did not expect health to trail it by this much. If the term you want lives in an extension, the odds that anyone else has written it are lower than the vocabulary's size suggests, and you should read the band beside it before you trust the name.

Attic and machinery hold only 12 and 6 terms, so one term moving would swing their shares; read those two rows more cautiously.

## Properties attached to more types are used more, without exception

Below I group the properties by breadth, the number of types Schema.org's definition lists them on, with the share of the group under 1,000 websites.

| Attaches to | Properties | In the bottom band |
| --- | --- | --- |
| 1 type | 1132 | 52.56% |
| 2 to 3 types | 304 | 28.29% |
| 4 to 9 types | 89 | 11.24% |
| 10 or more | 3 | 0.00% |

All groups with a figure together, 691 properties in the bottom band out of 1528.

A property defined on one type has one place it can be written. One defined on ten or more has ten places producing examples, documentation and tooling. This is the cleanest pattern I have found in the whole dataset, four groups in a row with no exception, and I trust it more than most single figures here. If you are choosing between two properties, the broadly attached one is usually the safer bet, because more of the web already writes it. A narrow property is still worth reaching for when it says a specific thing more accurately. Precision is sometimes worth more than borrowed adoption.

One property carries no breadth figure, interactionCount, and the widest group holds only 3 properties, too few to treat its 0.00% as a stable rate.

## How this is measured

I build both groupings from the same file behind the term-by-term table elsewhere on this site, which joins Google's monthly usage archive to a pinned copy of the Schema.org vocabulary. Section comes straight from that vocabulary's own field, so grouping by it needed no judgement call, unlike the ancestry walk the industry pages use to sort a type into a vertical. Breadth comes from counting how many types Schema.org's own definition lists a property as appearing on. I read that directly too. No inference. No judgement call.

Section is a different grouping from the one the industry pages on this site use. Those pages sort types by ancestry, walking them back through the vocabulary's own class hierarchy to a named vertical, and medical and health comes out with 88 types that way. Section groups all kinds of term, not just classes, by which part of the vocabulary Schema.org chose to publish them in. Medical and health holding 88 types by ancestry and the health section holding 280 terms by section are both correct, because they count different things. Section also needs no defending the way a derived grouping does. I read it straight off the field Schema.org publishes on the term, and you can check it on schema.org yourself. Add the sections' bottom-band counts back together and you get 1,161 terms out of 2,487. That is the same 46.68% I publish everywhere else on this site as the corrected share below a thousand websites.

For both groupings I then read the terms' bands from the July 2026 snapshot and counted how many sit in the bottom band, under a thousand websites, as a share of the group. The shares on this page are arithmetic on the counts already shown in the table above it, nothing hidden and nothing estimated. If you recount from the download and land one term off, check the snapshot month first.

I could have summarised each breadth group with a single number, averaging where the properties' bands sit on Google's ordered list of six. That produces a tidy-looking climb of its own, and it is tempting to publish precisely because it looks like the same finding in less space. I am not publishing it. A band is a position in an ordered list, not a quantity of websites. Averaging the positions gives you a figure with no unit and nothing real underneath it, the mean of a label, not a measurement of anything. The bottom-band share I publish instead is a real proportion of properties, it climbs in the same direction, and you can check it yourself by counting rows in the download. A property with no breadth figure is also kept out of the "1 type" group, because carrying no figure is not the same claim as carrying one.

Two different kinds of number sit side by side here. The section and breadth counts are exact, because they come from counting rows in a published file. The bottom-band share is exact as a proportion too, but it only tells you whether a term crossed one threshold, not how far below it sits or whether it has ever moved. A term used by nine websites and a term used by nine hundred are counted exactly the same way on this page. We cannot tell from band data alone why a widely attached property gets used more. We can only see that it does, in all four groups here.

Analysis © Eduard Dziak, licensed under the Apache License 2.0. Please credit eduarddziak.com with a link. Source data: Google and the Schema.org community, Schema.org usage statistics dataset. Rich result requirements: Google Search Central, licensed CC BY 4.0. Term descriptions: Schema.org, licensed CC BY-SA 3.0, each term linking to its own page. Crawl counts: HTTP Archive Web Almanac, licensed Apache License 2.0.