The effects of class rarity on the evaluation of supervised healthcare fraud detection models

Journal of Big Data

Table 4 Summary of Medicare datasets

Year	Part B		Part D		DMEPOS		Combined
Year	Fraud	%Fraud	Fraud	%Fraud	Fraud	%Fraud	Fraud	%Fraud
(a) By year
2012	546	0.062	–	–	–	–	–	–
2013	403	0.044	465	0.069	323	0.110	229	0.090
2014	285	0.030	329	0.047	193	0.068	154	0.061
2015	175	0.018	224	0.031	119	0.041	90	0.035
2016	99	0.010	135	0.018	75	0.026	55	0.021

PCC	Part B		Part D		DMEPOS		Combined
PCC	Fraud	%Fraud	Fraud	%Fraud	Fraud	%Fraud	Fraud	%Fraud
(b) Class imbalance and rarity
All	1409	0.038	1018	0.048	635	0.074	437	0.062
1000	1000	0.027	–	–	–	–	–	–
400	400	0.011	400	0.019	400	0.046	–	–
200	200	0.005	200	0.010	200	0.023	200	0.026
100	–	–	100	0.005	100	0.012	100	0.013