Both arrived as real charts before the sins existed, which is the better
order — the specimen makes the failure mode obvious.
"Bar Colours That Contradict Their Labels" (severity 2): categories that
already own a colour, drawn in a default palette, so Black is a green
bar. Nothing false, which is exactly why it's a 2 under our rubric — but
colour is pre-attentive, so the reader pays the cost on every glance.
"A Colour Scale That Changed Between Two Charts" (severity 4): the
Tagesschau incidence maps, rebinned from 25/50/100/250/500 to
20/35/50/100/200 three weeks apart while being presented as a
before-and-after. A colour key is an axis, and moving it mid-comparison
is the axis crime we don't police because a legend reads as formatting.
The bad chart there needed an explicit independent colour resolve —
Vega-Lite merges scales across a concat by default, which silently
unified the two legends and destroyed the entire demonstration.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ULE5RRxdQE1ebwefEd2eCM
Two new levers on a sin page. `wild[]` renders credited, linked
specimens between the explanation and the citations — first the
argument, then proof people actually publish this, then the sources.
`related[]` cross-links neighbouring sins and is resolved at build, so a
typo fails the build instead of shipping a dead link.
Both arrive with the first specimen: a Hungarian primary graphic whose
three slices read 38/22/19 — 79% — drawn as a full circle, so every
share is inflated by about 1.27x. Measured off the image, the 38% slice
occupies 173.6 degrees, or 48.3% of the pie.
Our published pie sin is about too many slices, so it didn't cover this;
"Pie Slices That Don't Sum to the Whole" is a new severity-5 page whose
before/after is two pies differing only in whether the remainder is
present. That sin is an omission, so `compareNote` replaces the standard
"same numbers, both charts" line.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ULE5RRxdQE1ebwefEd2eCM
The source-request loop paid for itself immediately — two of the five
corrected something rather than confirming it.
The Economist piece settles V1, the riskiest live claim, but our note
had over-claimed: truncating the scale is its *first* example, not one
of "several." Note rewritten to quote her. The same article turned out
to contain a dual-axis chart she caught herself on, now cited.
Datawrapper's color-scale part 1 refuted the assumption behind a queued
sin outright: it makes no argument against rainbow scales and endorses
multi-hue sequential gradients. The rainbow entry is now marked as
having no verified source at all, rather than ample backing.
The dual-axis post independently draws the same line we drew last turn
— of four uses only the alternative-scale case survives, their example
being F against C — and led to two references worth more than the blog
post: the Isenberg et al. study that tested dual-scale charts, and Few's
article working through the cases. Both ship without full metadata
rather than guessed metadata; queued.
Pie and stacked posts gave verbatim support, plus one correction: a
100%-stacked chart has two readable baselines, not one.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ULE5RRxdQE1ebwefEd2eCM
The pie page argued the form was the problem ("asks the reader to
compare angles") and then conceded a narrow exception; the dual-axis
page named the form in its title and rated it severity 5. Both read as
blanket bans, which is not the position — and blanket bans are how
dataviz advice turns into the folklore we're trying to replace with
citations.
The pie page now says outright that the chart type isn't the sin, the
workload is, and keeps the pie for the job it does well. The dual-axis
page is retitled for the actual misuse, drops to severity 4, and gains
a section on when a second axis is legitimate — the test being whether
you chose the alignment yourself.
Adds a severity rubric to CLAUDE.md so this stays consistent: 5 is
reserved for charts with no honest reading, and a form with legitimate
uses caps at 4.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ULE5RRxdQE1ebwefEd2eCM
"Canon" was leaking onto the public site — a nav item, a footer block, a
page title, a set of CSS class names. It was also driving content
decisions it had no business driving: the backlog was ordered around
which references were still unused, which is curation dressed up as
planning.
The page is now /references/, the list is documented as a bibliography
to grow rather than a canon to curate, and the backlog says plainly that
a sin earns a slot by being worth a page — sources are found to support
it, never the reverse.
Adds six sources (Cairo's Truthful Art, Few's Show Me the Numbers, the
Economist's audit of its own charts, Kosara's eagereyes, WTF
Visualizations, Datawrapper's dual-axis piece) and roughly doubles the
citations on the five published sins, to 5-7 each. Two of the new notes
point at sources that complicate our own position rather than back it.
The Economist essay ships without a URL rather than a guessed one.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ULE5RRxdQE1ebwefEd2eCM
Writes two sins off the backlog. The inverted y-axis is the egregious
one: the fill hangs from the top and the line descends while the values
climb, with every element individually defensible. Aspect ratio is the
quiet one: same twelve numbers, same y-range, only the shape of the box
changes.
Adds Cleveland, McGill & McGill 1988 to the canon — banking to 45 comes
from the shape-parameter paper, not the 1984 ranking already cited, so
citing the latter for it would have misattributed the claim.
Also renames sin slugs to match their retitled pages, and rewrites the
summaries that had started echoing those titles.
Gives line-chart points their mark color explicitly; "point": true was
falling back to Vega's default blue on a red or green line.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ULE5RRxdQE1ebwefEd2eCM
Titles are scanned in the gallery and recognized in a link, so they
should say what the sin is rather than pun about it. Retitles the three
published sins and the backlog's working titles, and records the rule in
CLAUDE.md: the title names the problem, the poke carries the voice.
Filenames are untouched, so existing URLs still resolve.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ULE5RRxdQE1ebwefEd2eCM
Its chart-type "what to consider" posts and four-part color-scale series
cover ground nothing else in the canon does. Adds a backlog entry it is
the leading authority on (stacked columns, where only the bottom series
shares a baseline), and closes the citation gap on the rainbow-color-scale
sin — that one now waits only on our own sequential-ramp validation.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ULE5RRxdQE1ebwefEd2eCM
Ranks the next six sins by working backwards from the references we
already vouch for: six of fifteen canon entries were uncited, and each
idle one points at a sin worth writing. Also records the candidates our
build-time Vega-Lite pipeline can't prove honestly yet, so we stop
rediscovering them.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ULE5RRxdQE1ebwefEd2eCM
Claude