DENSITY CURVE

Use when

• one distribution's shape for a reader who knows what a density is
• the curve is already computed and declared, with its bandwidth

Do not use when

• audiences who read areas as counts (CH-DST-01)
• several overlapping curves (small multiples, not overlays)

See instead

• bins are honest enough: CH-DST-01
• comparing shapes across categories: CH-DST-08

Alternatives

• CH-DST-01 (honest bins, no smoothing)
• CH-DST-08 (mirrored, per category)

Rules

• the density is supplied, never computed silently; the source line
• states the bandwidth
• one curve only; comparisons go to CH-DST-08 or small multiples
• y starts at zero

Never do this

• overlapping filled densities
• silent KDE with hidden bandwidth
• reading the y axis as counts

QA before delivering

• bandwidth stated in the source
• one filled curve
• y starts at zero
• source present

Data shape

{
  "title": "Clearance times peak near 20 days",
  "eyebrow": "CLEARANCE TIME SHAPE",
  "source": "Source: customs log, H1; KDE bandwidth 2.5 days",
  "unit": "%",
  "x": [
    "0",
    "5",
    "10",
    "15",
    "20",
    "25",
    "30",
    "35",
    "40"
  ],
  "series": [
    {
      "name": "All lots",
      "role": "key",
      "values": [
        1,
        5,
        11,
        19,
        24,
        18,
        12,
        7,
        3
      ]
    }
  ]
}