Engineering Science Letter
Vol. 5 No. 03 (2026): Engineering Science Letter - Articles in Press

Gradient Boosting Ensemble and SHAP-Based Explainability for Financial Literacy Classification in Urban Indonesia

Zulpa Salsabila (Universitas Mikroskil)
Tri Wulandari Ginting (Universitas Mikroskil)
Juliana Damayanti Manurung (Universitas Mikroskil)



Article Info

Publish Date
07 Nov 2026

Abstract

Although national surveys report rising financial literacy in Indonesia, losses from investment fraud and illegal peer-to-peer lending continue to increase, suggesting that aggregate indices obscure differences across knowledge, behavior, and attitude. This study developed a four-class literacy classification framework using gradient boosting models and SHAP-based explanations, drawing on an online survey of 606 respondents in urban North Sumatra. The instrument, adapted from OJK/SNLIK, consisted of nine knowledge, fourteen behavior, and four attitude items. SMOTE-NC was applied only within cross-validation training folds, so the validation and test data contained no synthetic observations. CatBoost obtained the highest cross-validated Macro F1 (0.8950) and achieved a test accuracy of 87.91% and a Macro F1 of 0.8587, comparable to XGBoost and Logistic Regression. Because the classes were derived from the same items used as features, these models largely approximate the scoring rule. A model based only on demographic and contextual variables, which avoids this dependence, reached a Macro F1 of 0.5347 against a majority-class baseline of 0.1579. Attitude items showed the highest per-feature SHAP contribution (0.321), partly owing to their larger scoring weight, although this dimension was less reliable (α = 0.6167). Gold price awareness, decision confidence, and risk preference were the most discriminative items.

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Journal Info

Abbrev

ESL

Publisher

Subject

Computer Science & IT Control & Systems Engineering Engineering Industrial & Manufacturing Engineering Materials Science & Nanotechnology

Description

Engineering Science Letter is an international peer-reviewed letter that welcomes short original research submissions on any branch of engineering, computer science, and technology, as well as their applications in industry, education, health, business, and other fields. Artificial intelligence, ...