BOXPLOT

Use when

• comparing many distributions compactly
• audiences trained on quartiles (analysts, engineers)

Do not use when

• general audiences (boxplots are widely misread; CH-DST-03)
• multimodal shapes (a box hides two humps; CH-DST-08 or CH-DST-09)

See instead

• few enough values to show raw: CH-DST-03
• the audience reads quartiles poorly: CH-DST-03

Alternatives

• CH-DST-03 (few raw values)
• CH-DST-08 (shape beyond quartiles, warn)

Rules

• five-number summaries are supplied, never computed silently
• median printed right of the max whisker, labeled on the first row
• whisker convention (min/max, not 1.5 IQR) must hold for every row
• shared zero-based scale

Never do this

• mixing whisker conventions across rows
• boxplots for general audiences without a reading key
• hiding sample sizes

QA before delivering

• min <= q1 <= median <= q3 <= max per row
• median labeled once
• unit once
• source present

Data shape

{
  "title": "Gate C reviews run three times longer at the median",
  "eyebrow": "REVIEW TIME BY GATE",
  "source": "Source: document register, H1",
  "unit": "days",
  "categories": [
    {
      "label": "Gate A",
      "min": 2,
      "q1": 4,
      "med": 6,
      "q3": 9,
      "max": 14
    },
    {
      "label": "Gate B",
      "min": 3,
      "q1": 6,
      "med": 9,
      "q3": 13,
      "max": 19
    },
    {
      "label": "Gate C",
      "min": 6,
      "q1": 12,
      "med": 18,
      "q3": 26,
      "max": 38,
      "highlight": true
    },
    {
      "label": "Gate D",
      "min": 3,
      "q1": 5,
      "med": 8,
      "q3": 12,
      "max": 21
    },
    {
      "label": "Gate E",
      "min": 2,
      "q1": 5,
      "med": 7,
      "q3": 10,
      "max": 16
    }
  ]
}