From shallow to deep learning in fraud – Lyft Engineering

One week into my Research Science role at Lyft, I merged my first pull request into the Fraud team's code repository and deployed our fraud decision service. No, it wasn't to launch a groundbreaking user behavior activity-based convolutional recurrent neural network trained in a semi-supervised, adversarial fashion that challenges a user to prove her identity -- it would be a couple of years before that. Embarrassingly, it was to remove a duplicate line of feature coefficients in a hand-coded logistic regression model rolled out a little less than a year before. This small bug exposed a number of limitations of a system built primarily for a different type of usage -- that of business rules that encapsulate simple, human-readable handcrafted logic. In our old worldview, models were simply extensions of business rules.