System Models in ecoinvent 3

A system model describes how activity datasets are linked to form product systems. The ecoinvent version 3 database offers three system models to choose from.

All system models are based on the same underlying data of real-world processes. Different types studies benefit from different modelling choices.

For users new to LCI databases, ecoinvent recommends using the cut-off system model when starting to work with ecoinvent version 3. This model can be easier to understand for first time users.

The cut-off system model applies the same modelling choices as ecoinvent version 1 and 2. This system model is therefore also recommended for experienced users looking for continuity with their previous work.

Cut-Off System Model

The system model Allocation, cut-off by classification, or cut-off system model in short, is based on the recycled content, or cut-off, approach.


The underlying philosophy is that a producer is fully responsible for the disposal of its wastes, and that he does not receive any credit for the provision of any recyclable materials.

APOS System Model

The system model Allocation at the point of substitution is also simply know as APOS system model.


The APOS system model follows the attributional approach in which burdens are attributed proportionally to specific processes.

Consequential System Model

The system model substitution, consequential, long-term is also know as consequential system model.


The consequential system model uses different basic assumptions to assess the consequences of a change in an existing system.