First Time Users

First Time Users

Why have the LCIA results of a product changes between versions?

Modeling of environmental impacts depends on an overwhelming number of assumptions, and it is sometimes hard to know which ones are the most important. It is equally difficult to know what are the consequences of changing an assumption.


When confronted with an impact score changing across different versions of the database, a detailed analysis is required to know the exact sources of the change. However, the potential reasons can be grouped in three categories:

Dataset updates

 

When newer or better quality data become available, or when an error is detected, values within the dataset at hand are changed. These can be quantities or nature of certain emissions, natural resource and intermediate products. If the dataset is multi-output and economic allocation is applied, a change in price will affect the results of the dataset. The allocation method might also have changed.

Supply chain changes

 

LCA takes into account the impact of the whole supply chain of products and services. If a dataset is changed, the impact of the other datasets will also be changed. This is especially true for commonly used datasets like electricity, transport and infrastructures. Linking a change in a dataset to a change of score in another dataset require a software tool and careful inspection of the supply chain.

Change in impact assessment methods

 

The characterisation factors provided by the method developers are regularly updated, and sometimes, there is a mistake in the implementation made by ecoinvent. The impact scores are obviously sensitive to a change of characterisation factors. More information about method implementation can be found in the following FAQ.

To held analyse changes in scores, a change report is produced for each new version of the database. The spreadsheet in annex of the report lists all the dataset changes that affect scores, and the word document clarifies the reasons for those changes. This report is available in the file section of ecoQuery.