CONTRA aims to help to design decision trees based on fuzzy logic. It has been developed by MEANS platform in collaboration with Christian Bockstaller, developer of the method (Bockstaller et al. 2017).

When most decision trees stand on boolean logic and strict threshold values between categories (e.g., « good » versus « bad »), fuzzy logic introduces progressive transitions between states. This allows to better represent intermediate situations and consider the variability and uncertainty.

In practice

The tool is accessible online pfmeans.inrae.fr/contra, and consists in:

• An user interface helping to design multi-level trees ;
• The possibility to use a range of membership functions to represent variables with fuzzy logic ;
• Import and export functionalities.

Direct calculation is also available for both intermediate and final indicators. Results can be visualised as synoptic and radar graphs to help with comprehension.