Boström,Henrik and Gurung, Ram B. and Lindgren, Tony and Johansson, Ulf - Archives of Data Science, Series A

Article Details

Title Explaining Random Forest Predictions with Association Rules
Authors Boström,Henrik and Gurung, Ram B. and Lindgren, Tony and Johansson, Ulf
Year 2018
Volume 5(1)
Abstract Random forests frequently achieve state-of-the-art predictive performance. However, the logic behind their predictions cannot be easily understood, since they are the result of averaging often hundreds or thousands of, possibly conflicting, individual predictions. Instead of presenting all the individual predictions, an alternative is proposed, by which the predictions are explained using association rules generated from itemsets representing paths in the trees of the forest. An empirical investigation is presented, in which alternative ways of generating the association rules are compared with respect to explainability, as measured by the fraction of predictions for which there is no applicable rule and by the fraction of predictions for which there is at least one applicable rule that conflicts with the forest prediction. For the considered datasets, it can be seen that most predictions can be explained by the discovered association rules, which have a high level of agreement with the underlying forest. The results do not single out a clear winner of the considered alternatives in terms of unexplained and disagreement rates, but show that they are associated with substantial differences in computational cost.