When viewing cost curves in Cost Benchmarking (both Basic and full Analytical Cornerstone), mills or machines are positioned along the curve and grouped into quartiles based on their cost competitiveness and their share of total market capacity.

How quartiles are defined

• The total capacity of the selected market is divided into four equal parts (quartiles).
• Example:
  If the selected market totals 5 million tonnes, then:
  • 1st quartile = lowest‑cost 1.25 million tonnes
  • 2nd quartile = next 1.25 million tonnes
  • 3rd quartile = next 1.25 million tonnes
  • 4th quartile = highest‑cost 1.25 million tonnes

How mills/machines are assigned

Each mill or machine is:

1. Ranked by cash cost from lowest to highest.
2. Accumulated by capacity along the curve.
3. Placed into the quartile where its cumulative capacity falls.

This means quartiles reflect capacity‑weighted cost distribution, not simply dividing the number of mills into four groups. Larger mills have a proportionally larger impact on quartile boundaries.