Interpretable vs learned encoders in fraud detection

Discover which categorical encoder achieves the highest AUC-ROC in fraud detection: embeddings vs CatBoost. Comparison on the IEEE-CIS dataset with 7 methods.

jueves, 2 de julio de 2026 • 2 min read • Q2BSTUDIO Team

Comparison of categorical encoders in fraud

In the field of financial fraud detection, handling high-cardinality categorical variables represents a significant technical challenge. Each transaction includes identifiers such as merchant codes, device types, or geographic locations that, if not properly encoded, can degrade model performance or introduce bias. Faced with this problem, data teams debate between two approaches: interpretable encoders —such as target encoding or hierarchical grouping encoding— which are auditable and transparent, and learned encoders, such as entity embeddings, which capture latent relationships between categories through dense vector representations.

Recent studies on real-world fraud datasets, with millions of records and positivity rates below 4%, have compared seven encoding techniques. The results show that embeddings generate a slightly higher area under the ROC curve, although they do not always dominate in precision-recall metrics. Boosted decision trees with interpretable encoding (such as CatBoost) offer very close performance, with the advantage that their decision thresholds are understandable to auditors. This balance between predictive power and explainability is critical in regulated sectors such as banking or insurance.

For companies seeking to implement robust anomaly detection systems, the choice of encoder must align with their compliance and scalability needs. A common strategy is to combine both philosophies: using interpretable encoders in the initial regulatory validation phase and later optimizing with embeddings once the model is deployed in production. This type of solution can be materialized through custom applications that integrate data pipelines, artificial intelligence, and automation workflows.

At Q2BSTUDIO, as a software and technology development company, we work to help organizations adopt these capabilities without compromising transparency or efficiency. Our artificial intelligence services for businesses range from feature engineering to model deployment in cloud environments, using both AWS and Azure to ensure high availability and security. Additionally, we complement these solutions with Power BI dashboards that allow real-time monitoring of fraud rates, and with AI agents that automate the review of suspicious transactions.

Cybersecurity is a fundamental pillar throughout this process, as fraud models handle sensitive data. Therefore, we integrate pentesting practices and regulatory compliance into every phase of development. Ultimately, whether prioritizing encoder interpretability or betting on learned representations, the key lies in having a technology partner that understands the particularities of the business and offers custom software that adapts to the specific challenges of each industry. This way, companies can achieve an optimal balance between predictive performance and data governance.

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