Assessment of catastrophic forgetting in continual credit card fraud detection

• Published in: Expert systems with applications 2024-09, Vol.249, p.123445, Article 123445
• Main Authors: Lebichot, B., Siblini, W., Paldino, G.M., Le Borgne, Y.-A., Oblé, F., Bontempi, G.
• Format: Article
• Language: English
• Subjects: Catastrophic forgetting; Continual learning; Continuous learning; Fintech; Fraud detection; Incremental learning
• ISSN: 0957-4174; 1873-6793
• DOI: 10.1016/j.eswa.2024.123445

The volume of e-commerce continues to increase year after year. Buying goods on the internet is easy and practical, and took a huge boost during the lockdowns of the Covid crisis. However, this is also an open window for fraudsters and the corresponding financial loss costs billions of dollars. In this paper, we study e-commerce credit card fraud detection, in collaboration with our industrial partner, Worldline. Transactional companies are more and more dependent on machine learning models such as deep learning anomaly detection models, as part of real-world fraud detection systems (FDS). We focus on continual learning to find the best model with respect to two objectives: to maximize the accuracy and to minimize the catastrophic forgetting phenomenon. For the latter, we proposed an evaluation procedure to quantify the forgetting in data streams with delayed feedback: the plasticity/stability visualization matrix. We also investigated six strategies and 13 methods on a real-size case study including five months of e-commerce credit card transactions. Finally, we discuss how the trade-off between plasticity and stability is set, in practice, in the case of FDS. •Fraud detection models must be updated continually to handle new fraud strategies.•They must balance plasticity (learn new patterns) and stability (remember old ones).•We show how to quantify both and discuss the trade-off for fraud detection.•We provide an extensive comparison of six strategies and 13 different models.•We present a real case study based on more than 50 million e-commerce transactions.