---
term: "Primary and secondary data"
aliases: ["primary data", "secondary data", "supplier-specific data", "background data", "foreground data"]
category: Concept
updated: 2026-09-08
canonical: https://verdatir.com/glossary/primary-and-secondary-data
publisher: Verdatir (https://verdatir.com)
---

# Primary and secondary data

> In life cycle assessment and carbon accounting, primary data are measured or collected directly from the processes in the product's own supply chain, while secondary data come from databases, literature or industry averages.

The distinction between primary and secondary data explains much of the difference in quality between two environmental studies of similar products.

## Primary data

Primary data are site-specific measurements or records from the processes under the reporting organisation's control or from its direct suppliers: metered energy use, weighed inputs and outputs, supplier-specific product carbon footprints. They are more representative but more costly to collect and maintain.

## Secondary data

Secondary data are taken from life cycle inventory databases, published studies, government statistics or industry averages. They fill the gaps that primary data cannot cover, especially for upstream processes many tiers away, but they are averages and may not reflect the actual technology, region or period.

## Foreground and background

Practitioners often describe the processes modelled with primary data as the foreground system and the database-driven remainder as the background system. Standards and PCRs specify minimum shares of primary data for certain processes.

## Where Verdatir fits

Verdatir records the data source and type behind every value, checks that primary-data requirements in the PCR or framework are met, and makes the primary/secondary split visible to reviewers and customers.

## Sources

- [ISO 14044:2006 — Life cycle assessment — Requirements and guidelines](https://www.iso.org/standard/38498.html)