About e2tree

Four researchers.
One algorithm.

e2tree is built by researchers at the University of Naples Federico II and K-Synth. The goal: make ensemble models auditable without sacrificing accuracy.

Host institution

University of Naples
Federico II

Spin-off

K-Synth
Naples, Italy

The team

Creators & contributors.

MA
Massimo Aria
Full Professor of Statistics for Social Sciences
University of Naples Federico II · K-Synth
AG
Agostino Gnasso
Researcher in Statistics
University of Naples Federico II · K-Synth
CI
Carmela Iorio
Associate Professor of Statistics
University of Naples Federico II · K-Synth
GP
Giuseppe Pandolfo
Assistant Professor of Statistics
University of Naples Federico II
MF
Marjolein Fokkema
Associate Professor of Methodology and Statistics
Leiden University, Netherlands

Co-author on the regression extension (2026 ASMBI paper)

Publications

The papers.

Two papers describe the method. The first covers classification, the second extends it to regression.

Computational Statistics · 2024 Read paper ↗

Explainable ensemble trees

Aria, M., Gnasso, A., Iorio, C., & Pandolfo, G.

Introduces the algorithm for classification. Defines the co-occurrence dissimilarity framework and the recursive tree-growing procedure, benchmarked on real datasets. The single e2tree matches Random Forest accuracy and is readable.

classification Random Forest explainability dissimilarity
BibTeX
@article{aria2024e2tree, title = {Explainable ensemble trees}, author = {Aria, Massimo and Gnasso, Agostino and Iorio, Carmela and Pandolfo, Giuseppe}, journal = {Computational Statistics}, volume = {39}, number = {1}, pages = {3--19}, year = {2024}, doi = {10.1007/s00180-022-01312-6} }
ASMBI · 2026 Read paper ↗

Extending Explainable Ensemble Trees to Regression Contexts

Aria, M., Gnasso, A., Iorio, C., & Fokkema, M.

Extends the method to regression. Co-occurrence weighting is adapted to account for response similarity between pairs, with a new impurity measure for continuous targets. Benchmarked against CART and GUIDE.

regression continuous response XAI
BibTeX
@article{aria2026e2tree_reg, title = {Extending Explainable Ensemble Trees to Regression Contexts}, author = {Aria, Massimo and Gnasso, Agostino and Iorio, Carmela and Fokkema, Marjolein}, journal = {Applied Stochastic Models in Business and Industry}, volume = {42}, number = {1}, pages = {e70064}, year = {2026}, doi = {10.1002/asmb.70064} }
Cite the package

Using e2tree in a paper?

Cite the relevant paper and the R package:

# Get citation information from R citation("e2tree")