POPULATION PYRAMID

two mirrored bar stacks around a labeled center gutter, one row per band. Needs: ordered bands (age, tenure, size class) with counts for two groups.

distributioncomparison

DL-01 AGRAW

Use when

two groups across ordered bands: age structures, tenure mixes
asymmetry between the two sides is the message

Do not use when

more than two groups (small multiples)
bands without a natural order (CH-MAG-03)

See instead

categories have no natural band order: CH-MAG-03
the two parts share one whole: CH-DEV-03

Alternatives

CH-MAG-03 (unordered categories)
CH-DEV-03 (two-part shares)

Rules

both sides share one zero-based scale, mirrored
band labels live in the center gutter
sides named above the first row, never a legend

Never do this

different scales per side (the classic pyramid lie)
unordered bands
more than two sides

QA before delivering

one shared mirrored scale
bands in order
sides named once
unit once
source present

Data shape

title	action title naming the asymmetry
source	bottom-left always
unit	on first left value
series_labels	[left_name, right_name], printed above the first row
bands	array of {label, a, b}, ordered top band first

Sample data (golden)

{
  "title": "Staffing thins sharply above 50",
  "eyebrow": "WORKFORCE BY AGE",
  "source": "Source: HR register, June",
  "unit": "staff",
  "series_labels": [
    "Women",
    "Men"
  ],
  "bands": [
    {
      "label": "60+",
      "a": 34,
      "b": 52
    },
    {
      "label": "50-59",
      "a": 86,
      "b": 140
    },
    {
      "label": "40-49",
      "a": 190,
      "b": 300
    },
    {
      "label": "30-39",
      "a": 270,
      "b": 410
    },
    {
      "label": "20-29",
      "a": 160,
      "b": 220
    }
  ]
}