Direct materials as a share of the cost of New Zealand heavy and civil construction, 2020

What it is. 17.6% of the total inputs of the heavy and civil construction industry: direct material inputs (structural metal 3.7%, sand, gravel, clay, stone and bitumen 3.4%, concrete and other mineral products 2.5%, diesel 1.7%, plaster, lime and paperboard 1.6%, wood 0.6%, other 4.0%).

Sample. Statistics New Zealand's 2020 input-output tables for the heavy and civil construction industry, as tabulated by Te Waihanga. The same paper reports mean quarterly material price change of 1.18% over 2010 to 2022 (Figure 1, nominal), and heavy and civil output prices rising 7.8% a year from 2020 to the March 2023 quarter against 2.4% a year over 2009 to 2019 (Table 1): price changes the schema cannot hold as a cost.

What it is not. Context only: how large this input is in the industry's cost structure, not a loss, an overrun or a price rise. It does not measure materials prices rising on a fixed price: the source does not say how many contracts were fixed-price or carried fluctuation clauses. Includes diesel (1.7%), which is also its own context figure. Whole industry, one year, not a contract's cost.

Where it came from

• New Zealand Infrastructure Commission / Te Waihanga (2023), Why do construction input costs change? The role of global and local factors · free copy
  Table 2, p.11, and section 1.4, p.10 · source record

Considered and set aside

• New Zealand Infrastructure Commission / Te Waihanga: Says structural steel, aggregates, concrete and cement, diesel and timber are about three quarters of material inputs, and that material prices follow world prices; it gives no share of a contract lost to a price rise.

context/nz_civil_inputs_materials_share · NZ · F42 ·the record ·link to this figure ·dispute this figure(or email support@demiton.io)