This chapter will first give a formal definition of fraud. You will then learn how to detect anomalies in the type of payment methods used or the time these payments are made to flag suspicious transactions.

Introduction & Motivation

Imbalanced class distribution

Cost of not detecting fraud

Time features

Circular histogram

Suspicious timestamps

Frequency features

Frequency feature for one account

Frequency feature for multiple accounts

Recency features

Recency feature

Comparing frequency & recency

In the second chapter, you will learn how to use networks to fight fraud. You will visualize networks and use a sociology concept called homophily to detect fraudulent transactions and catch fraudsters.

Social network analytics

Analyzing a network

Overlapping edges

Fraud and social network analysis

Looking for homophily in a network

Visualizing node attributes

Social network based inference

Relational vs non-relational models

Relational neighbor classifier

Social network metrics

Degree, closeness & betweenness

Adding network features

Fortunately, fraud occurrences are rare. However, this means that you're working with imbalanced data, which if left as is will bias your detection models. In this chapter, you will tackle imbalance using over and under-sampling methods.

Dealing with imbalanced datasets

How to deal with class imbalance?

Visualizing patterns in the data

Random over-sampling

Random under-sampling

Shrinking the majority group

Combining ROS & RUS

Synthetic Over-sampling

Have you met SMOTE?

SMOTE

From dataset to detection model

Build your own detection model

True cost of fraud detection

Imbalanced class distributions

In this final chapter, you will learn about a surprising mathematical law used to detect suspicious occurrences. You will then use robust statistics to make your models even more bulletproof.

Digit analysis using Benford's law

Benford's Law for first digit

Conformity of census data

Benford's Law for fraud detection

Conformity to Benford's Law

Fire insurance claims

Payments data set

Detecting univariate outliers

Computing robust z-scores

Boxplot

Detecting multivariate outliers

Multivariate outlier detection

Digit analysis and robust statistics

Chapter 1 datasets

Chapter 2 datasets

Chapter 3 datasets

Chapter 4 datasets

The Association of Certified Fraud Examiners estimates that fraud costs organizations worldwide $3.7 trillion a year and that a typical company loses five percent of annual revenue due to fraud. Fraud attempts are expected to even increase further in future, making fraud detection highly necessary in most industries. This course will show how learning fraud patterns from historical data can be used to fight fraud. Some techniques from robust statistics and digit analysis are presented to detect unusual observations that are likely associated with fraud. Two main challenges when building a supervised tool for fraud detection are the imbalance or skewness of the data and the various costs for different types of misclassification. We present techniques to solve these issues and focus on artificial and real datasets from a wide variety of fraud applications.

Unsupervised Learning in R

Supervised Learning in R: Classification

Learn to detect fraud using anomaly detection, social network visualization, imbalanced class distributions, and digit analysis, robust statistics in R.

Fraud Detection in R

Learn to  detect fraud with analytics in R.

Professor Data Science at KU Leuven

Social network components

Social network representation

Towards a network

Plotting a network

A network's edges and nodes

Let's practice!

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Social network analytics - Social network analytics

Social network analytics

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