Explaining the Unexplainable Machine Learning meets Statistical Interpretation
I work at the intersection of statistics and machine learning, developing methods
to make complex models genuinely understandable. Most of my research revolves around
ensemble models and the question of what they actually do.
01
AboutMe
I hold a PhD in Economics from the University of Naples Federico II. My
research sits at the boundary between statistical methodology and machine learning, with a focus
on Explainable Machine Learning — developing frameworks that make powerful
black-box models transparent and interpretable, in ways that are meaningful for researchers and
decision-makers alike.
The main thread of my work is E2Tree (Explainable Ensemble Trees), a method that
represents Random Forests and other ensemble models through a single, interpretable tree
structure. The goal is to produce explanations that are genuinely faithful to what the model
does, in both classification and regression settings. Several papers from this line of work have
appeared in leading statistical journals.
Beyond interpretability, I work on applied problems in health economics and social science —
predicting depression from national survey data, evaluating hospital quality, and studying the
relationship between scientific output and patient outcomes. I am part of the K-Synth
Research Lab and contribute to Bibliometrix, an R package used by
thousands of researchers worldwide for systematic literature reviews and science mapping.
My main line of research. I develop methods — in particular E2Tree — that
translate the internal logic of ensemble models like Random Forests into a single interpretable
tree, covering both classification and regression settings.
Machine Learning & Ensembles
Random Forests, XGBoost, and other ensemble methods, studied both for their
predictive properties and their interpretability. Part of this work focuses on how to measure
whether an explanation actually captures what a model does.
Bibliometrics & Science Mapping
Quantitative analysis of scientific literature, citation networks, and research
trends. I contribute to bibliometrix and Biblioshiny, open-source R tools used by researchers
worldwide for systematic literature reviews and science mapping.
Applied Health Analytics
Applying machine learning to health and clinical data: depression prediction from
national survey data, hospital service quality evaluation, and the relationship between research
output and patient outcomes. Part of two PRIN-funded national projects.
Applied Economics
Statistical and machine learning methods applied to economic questions — composite
indicators, stochastic evaluation frameworks, and public sector performance analysis. The common
thread is bringing methodological rigour to problems that matter for policy.
Applied Quantitative Methods
Applying quantitative methods across disciplines — from social surveys and
bibliographic databases to environmental and geophysical data. Some of the most interesting
problems sit at the boundary between fields, and that is where I find myself most often.
Live · Currently in Progress
What I'm working onnow
A live snapshot of the work currently moving forward — papers under review, methods in preparation, and projects in the pipeline.
Under Reviewsince 2025
A Family of Divergence Measures for Evaluating the Reconstruction Quality of Explainable Ensemble Trees
Defining a principled way to measure how faithfully a global surrogate (E2Tree) reconstructs the predictive behaviour of the underlying ensemble — across classification and regression.
Computational Statistics and Data Analysis
Under Reviewsince 2025
Evaluating the Quality of Hospital Services: A Stochastic Composite and Genetic-Matching Framework for Research and Non-Research Italian Public Hospitals
Comparing service quality between research and non-research Italian public hospitals through stochastic composite indicators and genetic matching.
Applied Stochastic Models in Business and Industry
Under Reviewsince 2026
Bayesian modelling of salinity profiles in the Volturno River mouth under depth dependence
Hierarchical Bayesian errors-in-variables model with Gaussian-process depth dependence for saltwater intrusion in the Volturno River. Temperature and dissolved oxygen identified as robustly associated covariates across seasons.
Stochastic Environmental Research and Risk Assessment
Under Reviewsince 2026
Compositional and Causal Drivers of National Life Expectancy
Investigating how socio-sanitary conditions and health system configurations shape national longevity trajectories, examining cross-country patterns in population-level lifespan dynamics.
Applied Stochastic Models in Business and Industry
Under Submissionsince 2026
Decision-Support Mapping of Pyroclastic Cover Thickness: Spatial Validation, Uncertainty and the Sampling-Requirement Curve
Spatial validation, calibrated uncertainty intervals, and a sampling-requirement curve for machine-learning maps of pyroclastic cover thickness around Somma–Vesuvius and the Phlegrean Fields.
Applied Spatial Statistics · Landslide Hazard
Under Submissionsince 2026
Disentangling the Causal Income–Longevity Gradient via Bayesian Functional Effect-Modification
A Bayesian panel hierarchy that lets each country's income–longevity slope depend on its 1960–1999 life-expectancy trajectory through a scalar-on-function term, accounting for about a third of the cross-country slope heterogeneity over 144 countries.
With Carmela Iorio & Bruno Damásio
Under Submissionsince 2026
Predict, Explain, Identify: A Framework for Assessing Predictive–Causal Divergence in Policy Analysis
A Predict–Explain–Identify (PEI) framework that treats predictive, explanatory, and interventionist importance as separate estimands, equipping each ranking with rank confidence sets so that reading a predictive ordering as a policy ordering can be tested variable by variable.
With Michelangelo Misuraca
Under Submissionsince 2026
An Explainable Decision-Support Framework for Longitudinal Machine-Learning Models
Extending E2Tree to panel data by separating between-unit from within-unit variation, proving that above an explicit intraclass-correlation (ICC) threshold no single greedy surrogate can be both interpretable and informative about within-unit dynamics.
With Massimo Aria & Carmela Iorio
Working Papersince 2026
Extending Explainable Ensemble Trees to Boosting-Based Ensembles: A Unified Framework for the Interpretation of Tree Ensembles
Extending the E2Tree explainability framework to gradient boosting ensembles (XGBoost, LightGBM), working towards a unified interpretation approach across bagging and boosting paradigms.
With Massimo Aria
Working Papersince 2026
Asymptotic Theory for the Normalized Loss of Interpretability (nLoI): U-Statistic Representation, Limit Distributions, and Two-Stage Consistency
Establishing formal statistical foundations for the nLoI index, deriving its asymptotic properties and limit distributions as both sample size and ensemble size grow.
Statistical Theory · E2Tree Framework
Working Papersince 2026
Inference for Conditional Shapley Values via Vine Copulas
Developing inference tools for conditional Shapley-based feature importance, enabling asymptotically valid confidence intervals without resampling.
XAI · Statistical Inference
Working Papersince 2026
Turning Regularization into Inference: A Cross-Fitted Test for Pairwise Interactions in Gradient Boosting
Connecting regularization mechanisms in gradient boosting to formal hypothesis testing for pairwise feature interactions, yielding calibrated p-values.
Gradient Boosting · Hypothesis Testing
Working Papersince 2026
e2tree: Explainable Ensemble Trees in R
An R package that generates a single human-readable tree explaining the latent similarity structure learned by a tree ensemble. Dissimilarity between observations is derived from terminal-node co-occurrence frequencies — not a competing predictor, but a faithful reconstruction of the ensemble's grouping logic.
R Package · XAI · CRAN
Working Papersince 2026
Mapping 25 Years of Random Forest: A Triangulation Framework for Bibliometric Reviews of Seminal Algorithms
A bibliometric study of the 99,502 articles citing Breiman (2001) on OpenAlex, introducing a triangulation framework that combines topic taxonomy, semantic abstract clustering (SPECTER2 + HDBSCAN), and bibliographic-coupling networks to map Random Forest's cross-disciplinary footprint.
With Luca D'Aniello
Open to Collaboration
Think you can contribute? Let's talk.
Do you see a point of contact, or have an idea worth developing together? Let's find out.
If any of these threads intersect with your own work — methodological (interpretability, ensembles, statistical frameworks) or applied (health, policy, science mapping) — I'd be glad to explore a joint paper, exchange data, or simply trade ideas over a coffee.
@article{aria2025extending,
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 = {2025},
publisher = {Wiley},
doi = {10.1002/asmb.70064}
}
2025
Predicting depression in Italy using random forest through the E2Tree
methodology
Aria, M., Gnasso, A., Rivieccio, R., & Siciliano, R.
@article{aria2025predicting,
title = {Predicting depression in Italy using random forest through the {E2Tree} methodology},
author = {Aria, Massimo and Gnasso, Agostino and Rivieccio, Roberta and Siciliano, Roberta},
journal = {Annals of Operations Research},
year = {2025},
publisher = {Springer},
doi = {10.1007/s10479-025-06758-7}
}
@article{adamo2021assessment,
title = {Assessment of Sleep Disturbance in Oral Lichen Planus and Validation of {PSQI}: a case-control multicenter study from the {SIPMO}},
author = {Adamo, Daniela and Gnasso, Agostino and others},
journal = {Journal of Oral Pathology \& Medicine},
year = {2021},
doi = {10.1111/jop.13255}
}
WP
A Family of Divergence Measures for Evaluating the Reconstruction Quality of
Explainable Ensemble Trees
Aria M., Gnasso A., Iorio C.
Computational Statistics and Data Analysis
Under Review
WP
Evaluating the Quality of Hospital Services: A Stochastic Composite and
Genetic-Matching Framework for Research and Non-Research Italian Public Hospitals
Gnasso A., Aria M., Beraldo S., Collaro M.
Applied Stochastic Models in Business and Industry
Under Review
WP
Bayesian modelling of salinity profiles in the Volturno River mouth under depth dependence
Gnasso A., et al.
Stochastic Environmental Research and Risk Assessment
Under Review
WP
Compositional and Causal Drivers of National Life Expectancy
Franchetti G., Gnasso A., Iorio C., Politano M.
Applied Stochastic Models in Business and Industry
Under Review
WP
Decision-Support Mapping of Pyroclastic Cover Thickness: Spatial Validation, Uncertainty and the Sampling-Requirement Curve
Gnasso A., et al.
Under Submission
WP
Disentangling the Causal Income–Longevity Gradient via Bayesian Functional Effect-Modification
Gnasso A., Iorio C., Damásio B.
Under Submission
WP
Predict, Explain, Identify: A Framework for Assessing Predictive–Causal Divergence in Policy Analysis
Gnasso A., Misuraca M.
Under Submission
WP
An Explainable Decision-Support Framework for Longitudinal Machine-Learning Models
Gnasso A., Aria M., Iorio C.
Under Submission
WP
Extending Explainable Ensemble Trees to Boosting-Based Ensembles: A Unified Framework for the Interpretation of Tree Ensembles
Aria, M., Gnasso, A.
Working Paper
WP
Asymptotic Theory for the Normalized Loss of Interpretability (nLoI): U-Statistic Representation, Limit Distributions, and Two-Stage Consistency
Gnasso, A.
Working Note for JRSS-B / JASA Submission
Working Paper
WP
Inference for Conditional Shapley Values via Vine Copulas
Gnasso, A.
Working Paper
WP
Turning Regularization into Inference: A Cross-Fitted Test for Pairwise Interactions in Gradient Boosting
Gnasso, A.
Working Paper
WP
e2tree: Explainable Ensemble Trees in R
Aria, M., Gnasso, A.
Working Paper
WP
Mapping 25 Years of Random Forest: A Triangulation Framework for Bibliometric Reviews of Seminal Algorithms
Gnasso, A., D'Aniello L.
Working Paper
2026
A statistical approach on environmental data towards a Digital Twin of
Volturno river transitional water system
Pacifico L., D'Adamo R., Matano F., Gnasso A., Scepi G.
SDS 2026 – Statistics and Data Science Conference Proceedings, Caserta
2025
"Can You Explain That?" E2Tree, SHAP, and LIME for Interpretable Random
Forests
Gnasso, A., Aria, M.
CLADAG-VOC 2025 · Studies in Classification, Data Analysis, and Knowledge
Organization. Springer, Cham.
@inproceedings{gnasso2025canyou,
title = {``{Can You Explain That?}'' {E2Tree}, {SHAP}, and {LIME} for Interpretable {Random Forests}},
author = {Gnasso, Agostino and Aria, Massimo},
booktitle = {CLADAG-VOC 2025 -- Studies in Classification, Data Analysis, and Knowledge Organization},
publisher = {Springer, Cham},
year = {2025},
doi = {10.1007/978-3-032-03042-9_20}
}
2025
From Prediction to Explanation: Interpreting Risk Factors in Health Survey
Analytics
Gnasso, A., Aria, M., Siciliano, R.
CLADAG-VOC 2025 · Studies in Classification, Data Analysis, and Knowledge
Organization. Springer, Cham.
@inproceedings{gnasso2025fromprediction,
title = {From Prediction to Explanation: Interpreting Risk Factors in Health Survey Analytics},
author = {Gnasso, Agostino and Aria, Massimo and Siciliano, Roberta},
booktitle = {CLADAG-VOC 2025 -- Studies in Classification, Data Analysis, and Knowledge Organization},
publisher = {Springer, Cham},
year = {2025},
doi = {10.1007/978-3-032-03042-9_21}
}
2025
Research excellence and patient perception: investigating the impact of
AHSCs' scientific output
Gnasso, A., Sacco, D., Celardo, L., Smecca, M.A., Alabiso,
C., & Spano, M.
IES 2025 – Innovation & Society · Invited Session IPS40
2025
From research to care: measuring the impact of AHSC on patient experience
Gnasso, A., Aria, M.
RC33 2025 – 9th International Conference on Social Science Methodology,
Naples, Italy · Session 44: Sustainability and High-dimensional Data Analysis
2025
Explainable Decision Tree Ensembles
Gnasso, A., Aria, M., Iorio, C., & Fokkema, M.
SIS 2024 · Italian Statistical Society Series on Advances in Statistics.
Springer, Cham.
@inproceedings{gnasso2025explainable,
title = {Explainable Decision Tree Ensembles},
author = {Gnasso, Agostino and Aria, Massimo and Iorio, Carmela and Fokkema, Marjolein},
booktitle = {SIS 2024 -- Italian Statistical Society Series on Advances in Statistics},
publisher = {Springer, Cham},
year = {2025},
doi = {10.1007/978-3-031-64447-4_21}
}
2024
The evolution of Explainable Artificial Intelligence (XAI): a preliminary
systematic literature review
Gnasso, A., Aria, M.
Book of Short Papers – ASA Conference 2024
2024
Inside the black-box models through explainable decision tree ensembles
Iorio, C., Gnasso, A., Aria, M.
Programme & Abstracts – COMPSTAT 2024
2023
Unlocking explainability in ensemble trees
Aria, M., Gnasso, A., Iorio, C., Pandolfo, G.
Programme & Abstracts – CMStatistics 2023 and CFE 2023, ECOSTA
2022
Twenty Years of Random Forest: preliminary results of a systematic literature
review
Aria M., Gnasso A., D'Aniello L.
IES 2022, pp. 225–230
2022
AI and ML in accounting and finance: a bibliometric review
Belfiore, A., Gnasso A., Cuccurullo, C., Aria, M.
JADT 2022 – 16th International Conference on Statistical Analysis of Textual
Data, Vol. 1, pp. 95–101
2021
Supporting decision-makers in healthcare domain. A comparative study of two
interpretative proposals for Random Forests
Aria M., Cuccurullo C., Gnasso A.
ASA 2021 – Book of Short Papers, Vol. 132, pp. 179–184. Firenze University
Press
No publications match
04
Talks &Conferences
Invited Seminars
Invited Seminar
"E2Tree: Explaining Decision Tree Ensembles"
Leiden University · Institute of Psychology, Methodology and Statistics
STAT-TALK Colloquium — February 2024
PhD Seminar
"Explainable Ensemble Trees (E2Tree)"
University of Naples Federico II · Department of Economics and Statistics
October 2024
PhD Seminar
"Applying E2Tree to Economic Contexts"
University of Naples Federico II · Department of Economics and Statistics
April 2025
Conference Talks
2026
▾
SDS 2026
Caserta, Italy · Mar. 2026
Environmental Data Science
A statistical approach on environmental data towards a Digital
Twin of Volturno river transitional water system.
2025
▾
RC33 2025
Naples, Italy · Sep. 2025
Sustainability and High-dimensional Data Analysis
From research to care: measuring the impact of AHSC on patient
experience.
CLADAG 2025
Naples, Italy · Sep. 2025
Recursive Partitioning and Related Methods
"Can You Explain That?" E2Tree, SHAP, and LIME for interpretable
Random Forests.
CLADAG 2025
Naples, Italy · Sep. 2025
Innovative Approaches in Machine Learning and Clustering
From Prediction to Explanation: Interpreting Risk Factors in
Health Survey Analytics.
IES 2025
Brixen, Italy · Jun. 2025
AI and Machine Learning
Research excellence and patient perception.
2024
▾
ASA 2024
Rome, Italy · Sep. 2024
AI and Machine Learning
The evolution of Explainable Artificial Intelligence (XAI).
COMPSTAT 2024
Giessen, Germany · Aug. 2024
High dimensional data analysis
Inside black-box models through explainable decision tree
ensembles.
SIS 2024
Bari, Italy · Jun. 2024
Advanced statistical methods
Explainable decision tree ensembles.
DSSR 2024
Naples, Italy · Mar. 2024
Unstructured data
The spread of Random Forest across scientific research fields.
2023
▾
CMStatistics 2023
Berlin, Germany · Dec. 2023
Explainability in machine learning
Unlocking explainability in ensemble trees.
ICDS 2023
Santiago, Chile · Nov. 2023
Multiblock Methods and Supervised Learning Algorithms
PhD Workshop
Naples, Italy · Sep. 2023
2nd Economics and Finance Workshop for PhD Researchers.
2022
▾
ECDA 2022
Naples, Italy · Sep. 2022
European Conference on Data Analysis.
JADT 2022
Naples, Italy · Jul. 2022
AI and ML in accounting and finance: a bibliometric review.
IES 2022
Caserta, Italy · Jan. 2022
Twenty Years of Random Forest: preliminary results of a
systematic literature review.
2021
▾
ASA 2021
Florence, Italy · Sep. 2021
Supporting decision-makers in healthcare domain.
Summer Schools & Workshops
Summer School in Science Mapping — Organizing Committee Member · International Edition · 3rd Edition, May 2025
Summer School in Science Mapping — Organizing Committee Member · Italian Edition · 4th Edition, May 2026 (upcoming) · 3rd Edition, May 2025 · 2nd Edition, May 2024 · 1st Edition, June 2023
Naples Summer School in Economics and Finance — Participant · Naples School of Economics · Naples, Italy
Conference Committee Roles
Local Committee Member — 16th International Conference on Statistical Analysis of Textual Data (JADT 2022) · Naples, Italy
Organizing Committee Member — Naples School of Economics: 2nd PhD and Post-Doctoral Workshop · Naples, Italy · September 2023
Local Committee Member — 15th Scientific Meeting Classification and Data Analysis Group (CLADAG 2025) · Naples, Italy
05
Teaching
Quantitative Methods
Metodi Quantitativi
Statistical Inference
Inferenza Statistica
Statistical Methods for Evaluation
Metodi Statistici per la Valutazione
Data Analysis
Analisi dei Dati
Statistics & Time Series Analysis
Statistica e Analisi delle Serie Storiche
Survey Methods
Indagini Campionarie
Statistics for Finance
Statistica per la Finanza
Student Support
Tutoring & Academic Assistance
Are you a university student and need support with your studies, thesis, or academic projects? I can
help you in the following areas:
The e2tree package implements the Explainable Ensemble Trees
(E2Tree) methodology. Rather than fitting a CART tree directly on raw data, E2Tree
learns the relational structure that the ensemble has already established: it extracts a
co-occurrence matrix from the trained model and uses hierarchical clustering to build a transparent,
interpretable dendrogram. The result is a global surrogate that faithfully approximates Random
Forests, XGBoost, and other boosting models.
Key Features
Global interpretability: converts ensemble models into a single explanatory
tree
Classification and regression: frequency-based and weighted connectivity
modes
Visual output: dendrogram-like visualisations with decision rules for each
cluster
XGBoost support: extended to gradient boosting in v0.2.0
rpart integration: outputs compatible with rpart objects
# Stable version from CRANinstall.packages("e2tree")
# Development version from GitHub
devtools::install_github("agostinognasso/e2tree")
Aria, M., Gnasso, A., Iorio, C., & Pandolfo, G. (2024). Explainable ensemble
trees. Computational Statistics, 39(1), 3–19. DOI ↗
Aria, M., Gnasso, A., Iorio, C., & Fokkema, M. (2025). Extending Explainable
Ensemble Trees to Regression Contexts. Applied Stochastic Models in Business and Industry.
DOI ↗
An R package for quantitative research in scientometrics and bibliometrics.
Provides a comprehensive workflow for science mapping analysis, supporting data import from major
bibliographic databases including Scopus, Web of Science, Dimensions, OpenAlex, PubMed, Cochrane
Library, and Lens. As a core developer team member, I contribute to development,
maintenance, and the web interface Biblioshiny.
Key Features
Import and convert data from 7+ bibliographic databases
Mapping Scientific Knowledge about Health for Decision-Making.
24-month PRIN project at the intersection of bibliometrics, knowledge synthesis, and health
policy (Code: 2022825Y5E, PI: Prof. Massimo Aria). Junior Researcher.
2023 – 2026
PRIN 2022 PNRR · MUR National Research
AHS Centres
The value of scientific production for patient care in Academic Health
Science Centres. A study on the relationship between research output and clinical
outcomes across Italian public hospitals (PI: Prof. Corrado Cuccurullo). Junior Researcher.
2023 – 2026
07
Network &Affiliations
I work with researchers across several institutions in Italy and abroad,
with shared interests in statistics, machine learning, and the methodological problems that sit between
them.
PhD in Economics · University of Naples Federico II
08
Consulting
Statistical Modeling
Regression analysis, hypothesis testing, survey design, and advanced
multivariate methods tailored to your research or business questions.
Machine Learning & Predictive Analytics
Development of classification and regression models using Random Forests,
XGBoost, and ensemble methods with a focus on interpretability and robustness.
Explainable AI (XAI)
Making black-box models transparent through interpretable tree structures,
SHAP values, LIME, and custom XAI solutions for high-stakes applications.
Bibliometrics & Science Mapping
Systematic literature reviews, citation analysis, research trend mapping,
and science mapping using Bibliometrix and Biblioshiny.
R & Python Development
Custom scripts, data pipelines, dashboards (Shiny, Streamlit), and R/Python
package development for reproducible data analysis workflows.
Data Visualisation & Reporting
Publication-quality charts, interactive visualisations, and comprehensive
analytical reports to communicate your findings effectively.
How It Works
1
Initial Consultation
We discuss your project goals, data availability, and expected outcomes. This
first meeting is free and without commitment.
2
Proposal & Planning
I prepare a tailored proposal outlining the methodology, timeline, and
deliverables for your project.
3
Analysis & Development
I carry out the analytical work, keeping you updated with regular progress
reports and intermediate results.
4
Delivery & Support
You receive the final output — reports, code, models — with documentation and
follow-up support as needed.
Who Can Benefit
Businesses & Startups looking to leverage data for strategic decisions
Research Groups & Universities needing advanced statistical support for
publications
Healthcare Professionals interested in clinical data analysis and predictive
modeling
PhD Students & Researchers seeking methodological guidance for their projects
Public Institutions requiring evidence-based analysis for policy evaluation
Let's Work Together
If you have a project in mind, feel free to reach out.