ISO 8559-4:2023

Overview - ISO 8559-4:2023 (coverage ratios for body measurement tables)

ISO 8559-4:2023 is part of the ISO 8559 series on size designation of clothes and defines how to calculate coverage ratios for body measurement tables. The standard explains how to compare two- or three‑dimensional size-intervals from a measurement table with a database of the targeted population to quantify how much of that population is “covered” by the table (often referred to as market share). Practical examples and a simplified one‑dimensional approach are provided in informative annexes.

Key technical topics and requirements

• Scope requirement: Applicable only when a database of body dimensions for the targeted population is available.
• Selected dimensions: Coverage ratios are calculated using two or three selected body measurements (e.g., bust, waist, hip). Theoretically extendable to more dimensions, but 4+ dimensions are not practical for illustration or interpretation.
• Area definition: Intervals from the body measurement table define rectangular (2D) or box (3D) areas. Lower interval limits are inclusive; upper limits are exclusive except for the last interval.
• Calculation principle: For each area i, coverage ratio = (number of cases within area i / total number of cases N) × 100. An overall coverage ratio is the sum of area-specific ratios.
• Visualization: Two-axis (rectangles) and three-axis (boxes) charts are recommended for visual analysis; annexes give concrete examples.
• Reporting requirements: Reports must reference ISO 8559-4, identify the body measurement table and population database, list selection criteria, state total cases (N), provide coverage ratios per area, cumulative ratios (if ordered), and an overall coverage ratio.

Practical applications and typical users

• Apparel manufacturers and brands use ISO 8559-4 to evaluate and optimize sizing tables to increase product fit and market coverage.
• Size engineers, fit specialists, and product developers apply coverage-ratio calculations during size-range design, grading and table optimization.
• Anthropometric researchers and data analysts use the standard to compare measurement tables against population databases and to produce defensible fit statistics.
• Retailers and market analysts employ coverage ratios to estimate potential market share by size offering and to inform merchandising and inventory decisions.
  Practical outcomes include data‑driven decisions on adding sizes, adjusting intervals, and communicating fit performance to stakeholders.

Related standards and content

• Part of the ISO 8559 series (size designation of clothes). The document references measurement‑table terminology consistent with other parts (e.g., interval definition from ISO 8559-3).
• Informative annexes (A–C) provide worked examples for 3D, 2D, and simplified 1D coverage-ratio calculations, useful for implementation and optimization workflows.

Keywords: ISO 8559-4, coverage ratios, body measurement tables, garment sizing, size designation, sizing optimization, population database, apparel industry.