Table 3.

Articles related to the classification and definition of medical fraud and abuse

Type of Fraud and Abuse in Healthcare	Study Type	Study Population	Article Title	Country	Year	Author
Fraud by service providers (sending invoices for services not rendered) Separating the billing for each stage of treatment Sending a bill for more expensive services Providing unnecessary services Providing non-covered treatment as covered medical treatment Fraud in the diagnosis and/or treatment history of patients Insurance fraud: Creating work history Creating a file for medical services that were not actually received Using someone else's coverage or insurance card illegally Counterfeiting refunds Making a profit/loss statement	Statistical methods divided into two classes, supervised and unsupervised methods	Comprehensive survey of the statistical methods applied to health care fraud detection	A survey on statistical methods for health care fraud detection [13]	USA	2008	Jing Li and et al.
Phantom billing - issuing a bill for services not rendered. Duplicate invoice - submitting identical copies more than once. Multi-layered invoice - providing a prescription for unnecessary ancillary services. Coding - Billing for services at a higher reimbursement rate than the services provided. Excessive or unnecessary services - Provides excessive or unnecessary medical services to the patient.	Sparrow's fraud type classifications	Relevant and important problem in Medicaid healthcare fraud detection	Predicting Healthcare Fraud in Medicaid: A Multidimensional Data Model and Analysis Techniques for Fraud Detection [14]	USA	2013	Dallas Thornton Roland M. Mueller
Referring patients to clinics, diagnostic services, hospitals, etc., with which the referring physician has a financial relationship. Identity fraud Manipulating the price of the device and services Incorrect coding and programming Differentiation of the treatment process Providing dual invoices Invoice for services provided by unauthorized personnel Providing unnecessary and maximum care	Systematic review	Literature related to types of health insurance fraud	Categorizing and Describing the Types of Fraud in Healthcare [15]	USA	2015	Dallas Thornton Michel Brinkhuis
Payment for services that have not been provided. Bribery: Patients who seek treatments that are potentially harmful to them (such as searching for drugs to alleviate addiction) and the prescription of services that are deemed unnecessary. Fraud: Intentionally billing for services that were never provided or rendered, unnecessary medical services, and altering prescriptions to receive higher reimbursements than the services provided. Abuse: Billing practices that directly or indirectly do not align with the goals of providing necessary medical services to patients, recognized professional standards, and reasonable pricing. Invoice for services not rendered (identity theft and phantom billing) Re-coding of services and items (high-level coding) Duplicate invoice Non-merge of copies (non-aggregation / creative invoicing) Non-essential medical services Excessive services	Case study	Medicaid health insurance program	Outlier based Predictors for Health Insurance Fraud Detection within U.S. Medicaid [16]	USA	2013	Guido Cornelis, Van Capelleveen
Fraud by service providers: - Requesting payment for services that were not provided. - Providing a separate invoice for each stage of treatment - Requesting a higher fee for services - Providing non-emergency medical services - Providing non-covered services as covered medical treatments - Falsifying diagnoses and/or patient treatment histories to approve medical procedures that are not actually needed. Insurance policyholders' fraud: - Forging employment records / being eligible for receiving insurance - Preparing prescriptions for medical services that were not actually received - Use of coverage or insurance card of other individuals Fraud by insurance companies: - Fake refund - Misrepresentation of profit and service statements Cheating in the conspiracy: - In such scams, more than one party is involved. For example, fraudulent activities may involve a patient and a doctor or an insurance company.		Machine Learning	7.37 million encrypted treatment records beginning from 2014 on 300,000 people sampled from Hangzhou, Zhejiang, China	China	2020	Conghai Zhang 1, Xinyao Xiao
Customer: Hiding a previous illness / chronic illness, manipulating previous health check-up findings Fake documents / forgery to meet insurance policy conditions Duplicate invoices and identity theft Participation in fraud rings, purchasing multiple insurance policies Staging and fake disability certificates Insurance representatives: Providing incorrect information to the customer and removing the insurance premium Tampering with health examination records before insurance coverage Customer guidance for hiding the truth Participation in fraud rings and facilitating policies under fictitious names Data forgery in group health coverage Provider: Overcharging, fake invoices, and invoices for services not rendered Unjustified methods, excessive tests, expensive medications Segmentation and code enhancement	Sub-groups efforts and deliberations over a short period of 12 weeks	Health insurance industry	FICCI Working Paper on Health Insurance Fraud [17]	India	2014	Hsrii
Fraud and abuse by service providers: Invoice for services that were never provided Providing more expensive services and methods Providing unnecessary medical services Providing non-covered treatment as covered medical treatment Making patients' diagnostic and/or treatment records Insurance fraud and abuse: Providing false reports to achieve a lower premium rate Creating work/eligibility records Counterfeiting medical prescriptions Fraud and abuse by the insurance company include the following: forgery of reimbursements and profit and service statements.	Architec-ture for health care insurance fraud and abuse detection	Health care insurance fraud and abuse detection system	An Effective Health Care Insurance Fraud And Abuse Detection System [18]	Nigeria	2020	Aderonke Ikuomola & Oluwafolake Esther Ojo
Medical identity theft Imaginary doctor Duplicate invoice Incorrect coding Separation of treatment stages Falsifying diagnoses or medical procedures to maximize payments Prescribing medication without examination Self-reference Promotion of unauthorized drugs Provision of services by unauthorized individuals Insurance record forgery Providing unnecessary medical services	Meta-analysis	Eighty eight literatures obtained from journal articles, conference proceedings and books based on their relevance to the research problem were reviewed	Meta-analysis of fraud, waste and abuse detection methods in healthcare [19]		2019	Rhoda Ikono and et al.