It's the return of a classic!
Dewey by the Numbers (2026-09-01)
| | Now in DDC 23 | New |
| Explicit assignable numbers in schedules (including built numbers) | 43,086 | 1,374 |
| Facets (building blocks from Tables 1-6 and internal add tables) | 12,289 | 333 |
| | Headings | Assignments |
| Relative Index terms | 115,351 | 119,856 |
| LCSH mappings | 45,031 | 50,187 |
| MeSH mappings | 417 | 491 |
Have you ever lost something in a move? It happened with us, when a script we used to gather some of these statistics was left on a server that got decommissioned. Developing a replacement had been on my to-do list for a while, and here we are: for the first time since September 2019, Dewey by the Numbers is back!
This returning quarterly feature from the Dewey blog gives a count of assignable numbers, both built and non-built, in WebDewey, as well as elements like table numbers that can be used in building but that aren't used alone. Today, these will all have URIs in Dewey linked data too. The right-side column used to be labeled "New in DDC 23", meaning from the launch of the 23rd edition in 2011 onward, but I've tweaked it to show what's new since the last report. Expect those numbers to be higher now than in future installments, since it's been seven years since the last one.
The second part of the graphic shows Relative Index terms and mapped LCSH and MeSH. The middle column counts headings, and right-side column shows how many number-to-heading assignments there are for that type of heading. We regularly map external terms to multiple numbers when appropriate; Relative Index terms can only be mapped to up to one table number and up to one schedule number.
