COLUMN + LINE

columns on a left scale, one line on a labeled right scale. Needs: ordered periods + one volume measure + one rate measure.

correlationchange-over-time

DL-01 AGRAW

Use when

a volume and a rate that move together over time
capacity vs utilization, output vs quality

Do not use when

two arbitrary series dual-axed to force a story
scales chosen to make the lines cross dramatically

See instead

both measures share a unit: CH-TIM-01
the relationship, not time, is the question: CH-COR-01

Alternatives

CH-TIM-01 (same units: two lines)
CH-COR-01 (relationship itself)

Rules

both scales start at zero, both are labeled with unit AND series name
bars muted, line primary: the rate is usually the story
never more than one line: a third scale is a lie

Never do this

unlabeled dual axes
non-zero baselines on either scale
three or more scales
two lines on one right axis

QA before delivering

both scales zero-based and labeled
series named at the scales
one line maximum
source present

Data shape

title	action title with a number
source	bottom-left always
x	ordered period labels
bars	{name, unit, values} on the left scale
line	{name, unit, values} on the right scale

Sample data (golden)

{
  "title": "Volume nearly doubled while on-time recovered to 86%",
  "eyebrow": "VOLUME VS QUALITY . 2026",
  "source": "Source: sample dataset v1, 2026-07-12",
  "x": [
    "Jan",
    "Feb",
    "Mar",
    "Apr",
    "May",
    "Jun",
    "Jul",
    "Aug"
  ],
  "bars": {
    "name": "Deliveries",
    "unit": "loads",
    "values": [
      42,
      48,
      55,
      61,
      58,
      66,
      72,
      78
    ]
  },
  "line": {
    "name": "On-time rate",
    "unit": "%",
    "values": [
      82,
      80,
      78,
      74,
      76,
      79,
      83,
      86
    ]
  }
}