The Higg MSI uses the best available data and this data is not static; we fully expect the data and results to change over time as better data is acquired and updated. There are several ways in which data in the Higg MSI may be updated:
- The first is when the background database is updated, such as annual GaBi Service Pack updates. In this case, the model isn’t changed and just the impacts are updated.
- The second is when a higher quality data model is available that better represents the specific process. The data quality is determined using four factors listed in the metadata and including the precision of the model and how recently the primary data was collected. In this type of change, the process scores tend to change more – sometimes up, sometimes down – but always with the intention that it is more accurate than before.
- The third is when new processes and materials are added to provide more detailed raw materials and manufacturing options to choose from. This means that materials can be modeled with more specific impacts, allowing better accuracy and detail when measuring material impacts.
We announce all data updates and users can view the change log to understand what has changed. In some cases, proxies and reasonable estimations based on expert judgment need to be made because of a lack of detailed information. We aim to be as transparent as possible about data quality; the metadata for each process lists the data quality rating and other modeling notes are included as well.