A bar says its whole length — that’s the contract the reader signs the instant they look. Length is value. So the moment the axis is cut off at 96 instead of 0, the contract breaks: a 2% difference stretches into a bar that looms three times taller than its neighbour. The numbers never changed; the drawing lied about them. Tufte gave it a number — the lie factor — and this chart’s is enormous.
The honest caveat, so this is a receipt and not a rule chanted from memory: truncated axes aren’t always a crime. A line chart of already-large values (a stock sitting at $412–$418 all week) can start above zero, because a line encodes position, not length — a flat line honestly reads as “not much happened.” The sin is specific to bars, whose length is the entire message.
So: bars start at zero. A difference too small to see that way isn’t a problem to paper over — it’s the finding.