This is a short note about a Dutch government back-end. It will, I promise, return to the practice.
On December 5, 2025, Rijkswaterstaat — the Dutch ministry agency that manages the country's roads, bridges, dikes, and water-management systems — replaced its long-running Waterwebservices back-end with a new system called Wadar. The new system supplies the data that flows to Waterinfo — the public-facing tool where any Dutch citizen can look up the water level at any of dozens of measurement stations on the IJsselmeer, the Waddenzee, the Maas, the Schelde, the IJssel, the Rhine — within a couple of seconds. The old system had been running since the early 2000s. The Wadar transition was carefully announced; the public-facing tool was preserved; the data continuity was preserved. It was, as a piece of public-infrastructure work, ordinary.
I learned about the transition because Maritza, who is from Yonkers but did her library science training at Pratt and has a particular interest in metadata, had it in a tab. She is a Dutch-engineering enthusiast in the way some people are model-railroad enthusiasts. She showed me the announcement at our weekly stand-up. The stand-up that week was about whether to expand CCH-003's waitlist transparency to include a 7-day moving average rather than a point estimate; we decided yes; this was the change in v2025.12. (The 7-day average is now in the cover ticker.)
Why the metaphor worked
The reason Maritza had it in a tab is that she has, for years, thought about this practice the way she thinks about a Dutch polder. Both are systems that exist because of constant, undramatic maintenance. Both are systems where the maintenance is the practice. Both are systems where the public is told, plainly, what the current water level is, where the dike is, where the dike has been repaired, where the dike was wrong, and where the next repair is scheduled. Wadar, the new back-end, exists because the old back-end was insufficient for the volume and the granularity of the questions being asked of it. The transition was not a marketing event. It was a maintenance event.
This is the discipline I want to say something about. We publish errata not because errata are virtuous but because the alternative is silence, and silence is the most expensive thing a clinical practice can produce.
What the errata page does for us
The errata page is the place where every change to a monograph is logged, dated, named, and linked to the prior text. The errata page is searched, on average, twice a week — usually by clinicians from other practices who are wondering how a small practice handles a particular policy update; occasionally by a patient who wants to know what we used to do, or who has a chart that pre-dates our current text and wants to read what was in effect when their care was given. The errata page is, in this sense, a reading room.
The errata page also has a smaller, internal effect: it makes it harder to lie to ourselves. When the policy change has to be written down, the policy change has to be defensible. The number of policy changes we have abandoned because they could not survive being written down is small but non-zero. (One example: a 2023 proposal to raise the membership rate, which I had planned to introduce as a "modest annual adjustment" and which did not survive the moment when I had to write down what was actually being adjusted. The proposal went back to the drawing board.)
What we owe the practice metaphor
We owe Maritza for the metaphor. We owe the polder system for the discipline. We owe Rijkswaterstaat for the demonstration that an institution can announce a back-end change with the same sentences it uses to announce a tide level. We owe the BNF, the USP, DailyMed, and the dozen other reference works whose fixed-field structure is the technical inheritance of this site.
Most of all, we owe the patients in our panel for being willing to read this kind of thing. The panel is 1,640 adults and 410 children and 312 BH patients. Some of them read the errata page. Some of them read the bulletins. Some of them have never visited the website past the front door. The point is that the document is here, in the public, dated and answerable, regardless of whether anyone reads it on any particular day.
What changed in v2025.12
- The cover ticker now reports the 7-day moving average waitlist for CCH-003, not the point estimate. Bulletin: this one.
- Three small typo corrections in CCH-001 (logged on the errata page, none affecting clinical content).
- Removed an external link to a deprecated CDC PrEP page in CCH-001 § Indications; replaced with the live CDC clinician guidance page.
That is the entirety of v2025.12. We will reissue at v2026.01 with whatever else has accumulated, and the errata page will continue.
References
- Rijkswaterstaat — Waterinfo — waterinfo.rws.nl.
- Rijkswaterstaat — Waterdata (Wadar) — rijkswaterstaatdata.nl/waterdata.
- British National Formulary — Pharmaceutical Press — pharmaceuticalpress.com/bnf-and-bnfc/online.
- U.S. National Library of Medicine, DailyMed — dailymed.nlm.nih.gov.
- Dutch Dikes — Typology — dutchdikes.net/typology.
- Buckland, M. K. Information and Society, MIT Press 2017 — mitpress.mit.edu.