**4.3 Life cycle inventory (LCI) and "data"/"background data" quality**

Primary or site-specific and secondary data is used in LCAs. Primary data are those collected directly from the production site relevant to the life cycle stages modeled. If there is no primary data available, then data from the LCI databases are used as secondary data.

Apart from environmental impacts from upstream supply chain of raw materials production, all production data are collected from production lines with reference to a base year. A general practice is to use average data of at least 1 year of a recent production period per declared unit production and should reflect actual production at the specific location.

Necessary background data (secondary data) relevant to life cycle stages are taken from the databases. While no guidelines indicate a timeframe or recommendations for databases, it is a good practice to share the versions and date of database releases used in the background study with the communication of the results.
