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TRICARE Operations Manual 6010.62-M, April 2021
Program Integrity
Chapter 13
Section 3
Statistical Sampling And Audits
Revision:  
1.0  AUDIT ASSISTANCE SOFTWARE
1.1  The contractor shall utilize the Regional Advanced Techniques Staff (RAT-STATS) software suite to support its auditing process. There are a number of well-known, reputable software statistical packages (e.g., SAS, R) that may be used in conjunction with RAT-STATS.
1.2  RAT-STATS when performing audit sampling. RAT-STATS is a statistical sampling software package created by the Office of Inspector General (OIG) to facilitate the auditing process.
1.3  RAT-STATS offers an assortment of capabilities which include, but are not limited to, random number generation, various sampling techniques, sample size calculation, and extrapolation.
1.4  The contractor shall download RAT-STATS from the Department of Health and Human Services (DHHS) website. A number of important statistical considerations related to the auditing process are summarized in paragraph 2.0.
2.0  STATISTICAL AUDIT METHODOLOGIES
2.1  The contractor shall use a technically sound statistical analysis method and sampling design.
2.2  The contractor shall use current statistical methods to determine sample size, design of sample and analytical methods as determined by the scope and the nature of the audit.
2.2.1  The contractor shall perform and design the audit individually on a case-by-case basis.
2.2.2  The contractor shall eliminate zero paid claims from the universe before the sample selection. This includes claims which were not denied, have allowable amounts, but zero dollars were paid.
2.2.3  Simple random sampling involves using a random selection method to draw a fixed number of sampling units from the frame without replacement (i.e., not allowing the same sampling unit to be selected more than once).
2.3  Stratified sampling involves classifying the sampling units in the frame into non overlapping groups, or strata. The stratification scheme ensures that a sampling unit from a particular stratum is more likely to be similar in overpayment amount to others in its stratum than to sampling units in other strata. Other sampling methods include, but are not limited to, multistage sampling, cluster sampling, and stratified cluster sampling.
2.4  The contractor shall utilize a qualified statistician when developing statistical samples.
3.0  PROBE SAMPLE AUDIT
3.1  The probe sample shall employ simple random sampling if it is to be used to evaluate the variability of overpayments in the claim universe. The results of the probe sample audit may trigger the need for the contractor to perform a Statistically Valid Random Sample (SVRS) audit or a 100% audit.
3.2  Statistically Valid Random Sample (SVRS)
3.2.1  Statistical sampling is used to investigate and project (e.g., extrapolate) the amount of overpayment(s) made on claims when a 100% audit is not used. Statistical sampling is commonly used in consideration of a large number of claims of potentially fraudulent claims and the dollar values associated with those claims given available resources to conduct the audit.
3.2.2  There are four key conditions that must be met in order for a SVRS to produce a valid extrapolation. These conditions are:
•  Properly defining the sampling unit, sampling frame, and the universe;
•  Applying an appropriate sampling methodology;
•  Calculating a suitable sample size; and
•  Sample the units sampled in the frame so that it is representative of the fraudulent claims.
3.2.3  Focusing the universe is performed by targeting specific claims which match the allegations of the case, and removing low dollar claims that will not be worth of recoupment.
3.2.3.1  The contractor shall select sampling units from the applicable sampling frames via a random sampling approach once the claims universe has been focused and evaluated to determine the sampling plan and methodology to be performed.
3.2.3.2  The contractor shall electronically generate sample sizes and random numbers customized for each audit performed using RAT-STATS software referenced in paragraph 1.0.
3.2.3.3  The focused claims universe shall be sorted in Internal Control Number (ICN) ascending order when the software’s sampled numbers are applied.
3.2.3.4  The contractor shall eliminate zero paid claims from the universe before the sample selection. This includes claims which were not denied, have allowable amounts, but zero dollars were paid.
3.2.4  The contractor shall record and achieve seed number of the random sample(s) so that the sample(s) can be recreated at a later date if necessary. The overall sampling plan and methodology may include a combination of sampling approaches consisting of one or more SVRS or 100% claims audit(s).
3.3  Stratified Sample
3.3.1  When the focused universe of claims includes diversity in a key characteristic such as paid dollar amounts or numbers of procedures billed within the claim, the efficiency of the audit is improved by employing a stratified sampling approach. If the potentially fraudulent claims represent diverse subpopulations the audit will be stratified by the contractor.
3.3.2  The contractor shall employ stratification when the universe of claims where the fraud is suspected to have occurred has a standard deviation greater than the average overpayment. This characteristic of the claims universe will be identified by the contractor using a random probe sample as described in paragraph 3.0, or by evaluation of the average and standard deviation of paid amounts using the software referenced in paragraph 1.0. The paid amounts represent the upper bound of possible overpayment for each claim when the average overpayment is unknown and can be used for estimation.
3.3.3  The stratification will then be employed to split the universe of claims where the fraud was suspected to have occurred into smaller, non-overlapping groups, or strata. Within a stratum, the claims are more similar to each other than to the other claims in the universe of fraudulent claims.
3.3.3.1  The contractor may use their discretion in identifying the number and characteristics of strata needed for an audit, such that each stratum has a standard deviation less than the average paid or overpayment amount. Each stratum’s subset of claims will then be sampled using a random selection method or a 100% audit. A stratified audit when properly designed will require the sampling of fewer claims overall or have improved statistical results for the generally extrapolated amounts, because the variability will be decreased in each stratum.
3.3.3.2  The contractor may apply additional sampling methods at their discretion including, but not limited to, multistage sampling, cluster sampling, and stratified cluster sampling.
3.4  One-Hundred Percent (100%) Claims Audit
The contractor may need to perform a 100% claims audit.
3.4.1  Situations may include a small stratum of high dollar claims which should be audited at 100% as part of stratified sampling approach. Alternatively, even lower dollar claims may need to be audited at 100% if the claims are not similar (in terms of procedure, paid amount, or other characteristics) to a large group of other claims in the universe.
3.4.2  In the vast majority of cases, the unit to be statistically sampled is the entire claim (which includes all paid line-items).
3.4.3  The contractor shall review the beneficiary’s entire Episode of Care (EOC) as part of the audit when the circumstances dictate.
3.4.3.1  In this case, the contractor shall discuss the specifics of this approach with Defense Health Agency (DHA) Program Integrity Office (PI) prior to selecting the sample(s) as there are ways of auditing the beneficiary’s EOC while still using the claim as the sampling unit.
3.4.3.2  In other unusual circumstances, a probe sample audit may be required (e.g., an audit that is not statistically valid). A statistically valid sample may or may not follow the probe sample audit.
3.5  External Audit - Beneficiary Inquiry
3.5.1  A secondary method of determining probable fraudulent practices is to conduct a verification of services with beneficiaries. This may be used to supplement a claims audit method, and address 100% of the beneficiaries who received services from a provider within a recent period of no more than one year. If the provider is seeing more than 50 beneficiaries for which claims have been submitted, a systematic sample may be used. (e.g., an interval of every fifth, 10th, claim). Generally, no less than 50 external verification letters shall be sent. A suspense period for responses to the verifications letters shall be 30 business days, with a follow-up either written, or by phone by the 30th business day. If the response is not received, the contractor may contact the beneficiary by phone to receive responses.
3.5.2  An external audit to the provider shall be conducted where a bill has been allegedly altered.
4.0  AUDITS
4.1  Audits are performed to examine and verify the accuracy of claims.
4.2  The contractor shall determine the type of audit appropriate for the particular circumstances on a case-by-case basis.
4.3  The contractor’s Program Integrity staff who perform records reviews and audits shall include an appropriate number of Registered Nurses (RNs), or equally qualified medically trained professional(s) and credentialed coding or credentialed medical billing professionals with the education and anti-fraud experience.
4.3.1  These personnel must have a thorough knowledge of TRICARE regulatory provisions, policy, and standards. The reviewer shall document, in detail, the rationale for the audit findings. The review must be dated and include the clinical specialty and qualifications of the reviewer and the signature (not initials) and the legibly printed name of the reviewer.
4.3.2  The contractor shall have a credentialed coding or credentialed medical billing professional or both on staff that has professional coding, reimbursement, and anti-fraud education and experience that provides support in the performance of medical records audits and program integrity functions.
4.3.3  In cases where clinical issues may be included in an audit, the contractor’s audit team shall include a member with clinical expertise in the area under review.
4.4  Reporting Audit Findings
4.4.1  The contractor shall report audit findings in a clear and concise manner in an automated spreadsheet, accompanied by a description of the audit with summary information in quantifiable terms.
4.4.1.1  The contractor shall include the findings on the DHA PI Audit Worksheet for each SVRS performed. For reporting requirements, see DD Form 1423, Contract Data Requirements List (CDRL), located in Section J of the applicable contract. The supporting audit spreadsheets shall provide the criteria used for determination of overpayments (e.g., no entry, not a benefit).
4.4.1.2  An analysis of the frequency of the occurrence of overpayments can lead to conclusions concerning further investigative actions. Other methods of analyses may be used concerning abusive practices.
4.4.2  The contractor shall include individual audit sheets documenting individual findings (which will then be summarized in the audit worksheet(s) (e.g., overpayment summary by claim line, audit summary report, extrapolation (sample) verification spreadsheet). Individual file folders, labeled with identifying information, shall be generated as appropriate and must contain all applicable documentation or data required to support the audit finding, which will include but not be limited to: claim copy, explanation of benefits, individual audit sheets, evaluation and management score sheet, and medical record documentation reviewed by the auditor.
4.5  Medical Necessity Audits for Medical or Mental Health Claims
4.5.1  The contractor shall perform medical necessity audits that are performed by a RN, or equally qualified medically trained professional, who can make medical judgments based on professional education and experience. This means RNs or qualified Physician’s Assistants (PAs) for medical claims. A qualified Licensed Practical Nurse (LPN) or Licensed Vocational Nurse (LVN), working directly under the close supervision of an RN or PA, may be used, if the contractor submits the LPN’s or LVN’s full resume and a detailed scope of authority and responsibility to the Contracting Officer’s Representative (COR) for approval before the LPN or LVN assumes a medical review role. For mental health claims, a clinical psychologist, psychiatric nurse practitioner, a psychiatrist or an equally qualified professional shall perform the audit.
4.5.2  These personnel shall have a thorough knowledge of TRICARE regulatory provisions, policy, and standards.
4.5.3  The reviewer shall document, in detail, the rationale for the audit findings.
4.5.4  The review shall be dated and include the clinical specialty and qualifications of the reviewer and the signature (not initials) and the legibly printed name of the reviewer.
4.5.5  Claims that the reviewer cannot make a determination on shall be referred to the contractor’s medical staff, or an external consultant at no cost to the Government. Use of medical staff or consultants is expected and required not only for initial reviews but post-payment analyses and audit requests from DHA PI.
4.5.6  The contractor shall involve physicians, consultants with a specialty appropriate to the case and allegations whenever the case is complex, physicians or consultants at no cost to the Government.
4.5.7  Other types of audits shall be performed to suit the allegations or aberrant billing practices such as probe, non-invasive, EOC, or calendar and are left up to the determination of the contractor. This shall include also utilizing other investigative techniques such as license verification and Internet research.
4.6  Prescription Records Audit for Pharmacy Claims Or Pharmacy Claims Audit
4.6.1  Audits shall be performed by a qualified trained professional, who can make judgments based on professional education and experience such as a certified pharmacy technician, a pharmacist, Doctor of Pharmacy or an equally qualified trained professional.
4.6.2  These personnel shall have a thorough knowledge of TRICARE regulatory provisions, policy and standards.
4.6.3  The reviewer shall document, in detail, the rationale for the audit findings.
4.6.4  The review shall be dated and include the clinical specialty and qualifications of the reviewer and the signature (not initials) and the legibly printed name of the reviewer.
4.6.5  Claims that the reviewer cannot make a determination on shall be referred to the contractor’s pharmacy staff (or if available, medical staff) or an external consultant at no cost to the Government. Use of pharmacy staff or an external consultant is expected and required not only for initial reviews but post-payment analyses and audit requests from DHA PI.
4.6.6  The contractor shall perform other types of audits to suit the allegations or aberrant billing practices such as probe, non-invasive, etc.
4.6.7  The contractor shall utilize other investigative techniques such as performing purchase verification, license verification, and Internet research.
4.7  Dental Necessity Audits for Dental Claims
4.7.1  Dental necessity audits must be performed by a qualified trained professional, who can make judgments based on professional education and experience such as a certified dental technician, a dentist, or an equally qualified trained professional.
4.7.2  These personnel shall have a thorough knowledge of TRICARE regulatory provisions, applicable contract, policy and standards.
4.7.3  The reviewer shall document, in detail, the rationale for the audit findings. The review shall be dated and include the clinical specialty and qualifications of the reviewer and the signature (not initials) and the legibly printed name of the reviewer.
4.7.4  Claims that the reviewer cannot make a determination on shall be referred to the contractor’s dental staff or an external consultant at no cost to the Government. Use of dental staff or consultants is expected and required not only for initial reviews but post-payment analyses and audit requests from DHA PI.
4.7.5  Other types of audits shall be performed to suit the allegations or aberrant billing practices (e.g., probe, non-invasive, EOC). This shall also include utilizing other investigative techniques such as license verification, and Internet research.
4.8  The contractor shall ensure compliance with the Alcohol, Drug Abuse and Mental Health Administration (ADAMHA) Reorganization Act, Public Law 102-321 (July 10, 1992) and implementing regulations including 42 Code of Federal Regulations (CFR) Part 2, when data requested includes services related to substance abuse or mental health and medical records requests.
4.9  Request for Mental Health Records - Psychotherapy Notes
The contractor shall not request that a provider submit psychotherapy notes as defined by “notes recorded by a mental health professional which document or analyze the contents of a counseling session and that are separated from the rest of the medical record”. The refusal to submit such information shall not result in the denial of the claim or allegations of fraud or abuse. The provider is responsible for extracting information to support that the claim is for reasonable and necessary services. If the provider does not submit information to substantiate that the services were medically necessary, the claim shall be denied.
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