Root-cause clusters in our atlases use labels taken from the log vocabulary: guard removal, lockout sequence skipped, walkway obstruction, chemical transfer line leak. We avoid umbrella terms like human error unless the log itself uses that phrase.
Each cluster panel lists the count, the median days-to-close, and one representative entry summary. Executives scan counts; EHS staff read the representative entry.
When two clusters overlap, we show a Venn-style inset rather than forcing incidents into a single bucket. Overlap often reveals training gaps that single labels hide.
Colour in cluster charts follows our brass-and-ivory palette: oxidized green for closed actions, antique gold for open actions nearing deadline, charcoal for overdue items.
Committee chairs receive a one-page legend explaining every label and its source field in the incident form. That page reduces debate about definitions during the first ten minutes of every briefing.