# Important links - [Website][1] - [Development blog][2] - [Source code][3] # Description The Ocelot project is a joint effort by the Paul Scherrer Institut and the ecoinvent centre to build an open source library for applying system models in life cycle assessment. System models are a set of linking rules and assumptions, including how to handle activities that produce multiple outputs, how to construct markets in time and space, what products are substitutable, and who gets credit for the production of recyclable materials. There are currently a large number of system models used both in life cycle assessment, and in environmental product declarations and footprinting. For example, the ecoinvent centre releases three different versions of the ecoinvent database, each with their own system model. However, for the general community it has been difficult to examine all the explicit and unspoken assumptions and choices that each system model includes, despite knowing for over 15 years that the uncertainty due to these choices is significant. The Ocelot project aims to provide a new approach to this problem through an open-source implementation of a linking framework. Initially, we will implement the cut-off and long-term consequential system models in ecoinvent 3.2. Due to the structure of Ocelot, however, users will also be able to make minor modifications on existing models or, with larger efforts, even create their own system models. As the importance of LCA continues to grow, the scrutiny and pressure on the scientific basis of LCA will increase. Providing more transparent and easily modifiable linking algorithms will allow the Ocelot team and the research community to carry out the systematic tests needed to examine the robustness of the various system models, including isolating the effects of individual choices; the effects of different assumptions; and how appropriate certain assumptions are for various sectors of the economy. As a secondary objective, Ocelot also aims to make the existing system models in ecoinvent easier to understand. Each step in the processing pipeline will be clearly and publicly identified, documented, and explained. [1]: https://ocelot.space/ [2]: https://blog.ocelot.space/ [3]: https://github.com/OcelotProject