Frequently Asked Questions

Below are answers to commonly asked questions organized into six categories.

Data Release & Request Process

Q. What rule governs how MHDO releases data to the public?

A. MHDO Rule Chapter 120 governs the MHDO’s release of data to the public. You can find a copy of that rule on our Rules and Statutes page.

Q. How do I request data from MHDO?

A. You can find out how to request data on our Request Data or Reports page.

Q. What data can I request?

A. The Data Availability page lists the available data sets. It also shows the organization types that supply the data, the information contained in the data, and the time periods the data represent.

Q. What is the comment period and who can submit a comment?

A. The comment period is the period of time a data request is publicly posted for comment. The comment period allows the data providers and the public to review the data request and submit concerns about the data release to the MHDO. MHDO posts new data requests to its website, on its Current Data Request page, on the first business day of every week; MHDO also sends an electronic notification to the data providers who submit the data and other interested parties, notifying them of new data requests. The comment period is 30 business days after the request first appears on the MHDO website.

Q. How much does it cost to access data from MHDO?

A. MHDO’s data access fees can be found on our Pricing Information page.

Data Availability

Q. What is the difference between the APCD (All Payer Claims Data) data and the Hospital encounter data?

A. Payers submit claims data to the MHDO and hospitals submit hospital encounter data for all encounters inpatient and outpatient as well as for their provider based clinics.

The APCD contains health care claims paid for Maine residents by insurance companies licensed in Maine. It also includes Medicare claims paid for Maine residents and MaineCare (Maine Medicaid) claims. The submissions include files with member eligibility, medical claims, pharmacy claims, and/or dental claims information. These data contain information on the amounts that insurers paid for services. Please see the Data Availability page to see what types of entities submit data for each source and what data are available.

Hospital encounter data are submitted by hospitals and provider-based clinics in Maine. These submissions contain data for every service provided to each patient, regardless of how they were paid (commercial insurer, public, uninsured). However, these data do not include financial information on amounts billed or paid. Please see the Data Availability page to see what types of entities submit data for each source and what data are available.

Q. Does the MHDO data (APCD and hospital encounter) include patients who are uninsured and/or who paid for their care, or only data from payers?

A. Hospital encounter data does include patients who are uninsured but does not include payment information. The Maine APCD does not contain data on patients who are uninsured.

Q. What are the main differences between Level I and Level II data sets?

A. MHDO's Level I data sets are considered de-identified data which means the data elements do not directly or indirectly identify an individual patient and for which there is no reasonable basis to believe that data can be used to identify an individual patient.

MHDO’s Level II data sets are considered a limited data set which includes limited identifiable information specified in the HIPAA regulations. Level II data sets may only be used in ways that maintain individual anonymity.

For more information about which fields are included in the Level I and Level II data sets, refer to the Release Included Elements.

Q. I am interested in purchasing a Level II data set. Do I need to purchase both the Level I and Level II data sets to obtain all the releasable data fields available?

A. No, the Level II data set contains the data elements in Level I, so there’s no need to purchase both.

Q. Is it possible to obtain patient level and provider level data? Is this identified or de-identified data?

A. In the Level II data sets for both APCD and Hospital encounter data, de-identified patient data are available and each patient has a MHDO assigned unique identifier. Identifiable provider data is available for both the APCD and hospital encounter data. The APCD data dictionaries are available and provide details on the specific data elements. Some highlights of the provider data include facility name, facility code, geographic information, service provider state, data processing center code and a national provider identifier where appropriate. For the Hospital encounter data, a unique hospital or clinic is provided for each encounter with the name of the facility, geographic location, and de-identified ordering and performing provider. (Note we are working on preparing data dictionaries for the hospital encounter data which will be available in 2017.)

General Data Questions

Q. What format are the data sets released in?

A. MHDO Data sets are released in fixed-width text (.txt) files. These can be imported on a variety of platforms and are widely recognized by data management and statistical analysis tools. Data users typically use a database like SQL server or a statistical analysis package like SAS.

Q. Is there a way to link the APCD and Hospital encounter data sets together?

A. No, not at this time as there are no direct data elements released in the data that would allow the linkage between the All Payer Claims Database (APCD) and the Hospital encounter data. The MHDO has discussed the feasibility and utility of linking these data sets internally and making available as a combined data set. At this time there is limited utility in developing one patient index across the different data streams (claims and hospital data). Instead MHDO is focusing our resources on making sure that we have the data elements needed to identify unique individuals in the data streams so that we can accurately link records internally and release de-identified records.

Q. Once I’ve been approved to receive MHDO data, how will the data be sent?

A. When the data are ready to be released, you’ll receive an e-mail from MHDO's data vendor, NORC with the links to the data release files to be downloaded. We use the file sharing platform Accellion to ensure a secure file transfer. If you do not have an Accellion account, you’ll need to register for one.

The following instructions will be included in the e-mail:

To begin downloading the files you’ll need to click on one of the links. Because this is a secure download you will be asked to enter the address that received the e-mail. If you do not already have a download account, you will receive a second verification e-mail. Click on the link in that e-mail, choose a password, and you will then be able to authenticate and download the files.

Q. I received an email to download MHDO data, but I need one of my colleagues to download the data. Can I forward them the email?

A. No, the data transmittal email cannot be forwarded to others. Only original recipients are authorized to download the files. Please contact MHDO to modify the Data Custodian of your request if needed.

Q. How long will I have to download the data?

A. You have 90 days after receipt of the e-mail with the instructions to download the data. If you need to access the data after this time you will need to e-mail the MHDO at and include your Data Request Number in the subject line. The e-mail should explain why you need extended access to download the data files.

Q. What do I do if I have questions regarding the data?

A. Send your questions in an e-mail to MHDO at with your Data Request Number in the subject line of the message.


Q. Where can I go to see which data elements are included in the APCD?

A. The APCD data dictionaries are available on our MHDO Claims Data Dictionaries page.

Q. Are APCD data dictionaries the same across all payers (e.g., commercial, MaineCare and Medicare)?

A. Yes, the data dictionaries apply to all claims records regardless of payer.

Q. Does your medical claims database include both professional and facility claims?

A. Yes, both professional and facility claims are included in the Maine APCD.

Q. Do I need to request the Practitioner Identifiable data elements if I am looking to identify a hospital as a provider in the APCD data?

A. No, you do not need to receive the Practitioner Identifiable data elements to identify a hospital. A facility table is provided in both the Level I and Level II data releases. The table allows data users to link the hospital identifier in the data and determine the claim lines associated with each hospital.

Q. Does the APCD contain denied claims?

A. No, the MHDO claims data submission, Rule Chapter 243, specifically excludes denied claims from all medical, pharmacy, and dental claims file submissions. When a claim contains both approved and denied service lines, only the approved service lines are included as part of the health care claims data set submittal. You will typically see reversals in the data with a claim status code of 22 and negative values in the data are adjustments to previous paid claims. Generally, payers fully reverse a claim line before issuing a replacement. However, we know that there is some variance in this practice. For instance, some Payers will only issue a partial adjustment (meaning that the sum of the entire claim still gives you the right bottom line figure).

Q. What is the difference between the APCD claims datasets and the eligibility data sets?

A. Claims data sets include:

  • all members that had a health care insurance claim
  • line item payment detail related to the procedures claimed

Eligibility data sets include:

  • covered members for a payer for each month regardless of whether the member had a claim
  • county and/or town and zip code information on the members as listed above
  • information on what plans members had coverage under and the months they had coverage for each plan

For more information, please view the data dictionaries.

Q. Will the information provided include carriers that cover employer groups who reside in Maine?

A. The Maine APCD includes all payors as defined by MHDO with greater than $2,000,000 of adjusted premiums or claims processed per calendar year. Please see the Data Availability page to determine if a specific payer would be included in the requested dataset. . Note: As a result of the Gobeille v. Liberty Mutual decision (March 1, 2016) submission of claims data for self-funded ERISA plans is no longer a State requirement. However, we are accepting these data submissions on a voluntary basis.

Q. Does the All Payer Claims Database (APCD) include Medicare Advantage?

A. Yes, the MHDO receives Medicare Part C claims data also referred to as Medicare Advantage Plans. There is a flag in the claims that identifies Medicare plans administered through commercial payers. We have separated these from Medicare plans administered by the government. Therefore, you can determine which claims were Medicare Advantage claims.

Q. Does the APCD Pharmacy Claims include all payers (i.e., MaineCare, Medicare, and private insurance)?

A. The APCD includes pharmacy claims data from the private insurance companies and from Medicare Part D plans (outpatient Prescription Drug Insurance). Part D is provided only through private insurance companies that have contracts with the government.

Q. In the APCD, is there any kind of identifier that we can use to follow an individual across insurers and over time? Are encoded beneficiary identifiers the same across all parts of the data, and would it be possible to see claims of the same individual when they switch from a commercial plan into Medicare/Medicare HMO?

A. Every claim and eligibility record is assigned a MHDO de-identified member number to allow the tracking of de-identified individuals across time and between payers; however, due to variations in how payers supply eligibility information, sometimes the same individual may be assigned more than one MHDO de-identified member number. In general, the Medicare data includes eligibility data that allows us to assign a de-identified member number consistently The Medicare Advantage data are not always submitted with consistent member eligibility data. This is also an issue with pharmacy claims, where a number of plans only provide a contract number that cannot be tied to an individual in the medical claims. For Medicare Part A and B claims data administered by the government, we receive only medical claims. For Medicare Advantage plans, we receive both pharmacy and medical claims.

Q. What geographical identifiers are available in the APCD data? From the data dictionary, it seems that for both plan members and providers, city name, state/province, and ZIP code are available. Could you confirm this?

A. The geographical data elements available in the APCD data are as follows for both providers and de-identified individuals:

  • County
  • City
  • State
  • Zip

Geographical information related to city, state and zip has to be specifically requested and justified during the data request process.

Q. Using the claims information, I need to be able to track the exact health insurance plan for each submitted claim. What are the plan identifiers in your data?

A. The APCD data includes a field which indicates the payer and product type (HMO versus PPO, etc.) but not the specific plan identifier. The claims file has the claim filing indicator code and the eligibility file has the insurance type code which can be referenced in ASCx12.

Q. How are medical claims versioned in the data?

A. According to Rule Chapter 243, the original claim will have a version number of 0, with the next version being assigned a 1, and each subsequent version being incremented by 1 for that service line. There are some payers that are versioning claims differently from what is described in Rule Chapter 243. We have asked these payers for their methodologies and will post them and update this FAQ by July 2017.

Q. Is there a way to identify prescriptions that were filled through mail-order?

A. There is no mail-order indicator, however the pharmacy NPI is released which allows for the pharmacy to be identified.

Q. Can the same member identifiers in past files, be used with future files?

A. The member IDs we assign are consistent across time so that data users don’t need a full data refresh with each data release- when we send a new quarter of data, the user should be able to append it to the previous MHDO data that you received. For every quarterly release, we include information on the member match to eligibility, which represents the percentage of claims that have a matching eligibility record for the member. In a recent release, which included all of calendar year 2016 for commercial data, Q2-Q4 2016 for MaineCare (Medicaid) data and Q3-Q4 2015 for Medicare data, we had high overall match rates – 97.9% for medical claims, 96.2% for dental claims and 98.7% for pharmacy claims. MHDO is looking into the stability of the member identifiers across time and will follow up with users in 2017.
Note: Every claim and eligibility record is assigned a MHDO de-identified member number to allow the tracking of de-identified individuals across time and between payers; Note: due to variations in how payers supply eligibility information, sometimes the same individual may be assigned more than one MHDO de-identified member number.

Q. How does the MHDO define runout?

A. Runout claims data is data with an incurred date within the data request period that is paid after the data request period ends. MHDO’s default runout period is 6 months. Example: if you request MHDO claims data through Q4 of 2016, you will receive data through Q2 2017 (the 6-month runout period will include records incurred in 2016 that were paid during Q2 of 2017).

Q. Where do I find the insurance type or product code that indicates the type of insurance coverage the individual has?

A. Refer to MHDO Rule Chapter 243 for the source information for these fields. Depending on the file type (medical, pharmacy, dental, eligibility), this information is released in the following fields.

  • Medical Eligibility: ME912_MHDO_PRODUCT
  • Medical Claims: MC913_MHDO_PRODUCT
  • Dental Eligibility: DE912_MHDO_PRODUCT
  • Dental Claims: DC912_MHDO_PRODUCT
  • Pharmacy Claims: PC912_MHDO_PRODUCT
  • Pharmacy Eligibility: PE912_MHDO_PRODUCT

Q. How do I interpret the Medicare product codes?

A. Below is a list of ME912_MHDO_PRODUCT codes that are non-standard and specific to Medicare.

  • 1 = PART A ONLY
  • 2 = PART B ONLY

Q. How is Medicare Part C and D coded?

A. This information can be found in the MHDO_PRODUCT fields in the release files.
In the eligibility files, these are the codes:

  • HN = Medicare Part C
  • MD = Medicare part D

In the claims files, these are the codes:

  • 16 = Medicare part C
  • MD = Medicare Part D

Q. Does the MHDO get date of death for Medicare patients from CMS and if so, is it included in any of the MHDO releases?

A. Date of Death is not a releasable field and not included in our data releases.

Hospital Encounter Data

Q. Do you have data dictionaries for the hospital encounter outpatient and inpatient data sets?

A. Not as this time; however data dictionaries for our hospital encounter data will be available in late 2017. In the interim, the Hospital Encounter Release Elements document is available to assist users.

Q. In the MHDO Hospital data, does Emergency Department data include both Inpatient and Outpatient data sets?

A. Yes, Emergency Department (ED) data is a subset of the Hospital for both the Inpatient and Outpatient data sets. The ED data follows the same format as the Outpatient Hospital data. It is processed with the Inpatient and Outpatient data and is available for the same time periods as these datasets.

Effective with the 2015 hospital data there is an ED Flag in both the Inpatient and Outpatient data. This flag is set based on the presence of ED-related revenue codes present for each encounter in the Inpatient data and either ED-related revenue codes or ED-related CPT codes in the Outpatient data.

Please refer to the 2015 Inpatient Release Notes (found on our Hospital Data page) for important details about the MaineGeneral Medical Center's ED-related revenue codes from July 2013-September 2015 that prevent the ED Flag from being set properly.

Q. Where can I go to see what data elements are included in the Hospital data sets?

A. You can find the Hospital Encounter Release Elements document on our Hospital Data page.

Q. What is the MHDO-assigned Medical Record Number (MRN)?

A. The MHDO-assigned Medical Record Number (MRN) is an obfuscated and transformed version of the MRN that is submitted by facilities to uniquely identify patients. Data users are reminded that the MHDO-assigned Medical Record Number generally cannot be used to track individuals between facilities; the same MRN may be used at different facilities to represent different individuals. Also, even within the same facility, an individual may not retain the same MRN across time; when hospitals merge or when they transition to new data systems, new MRNs may be assigned. The MHDO has no control over the MRN assignment policies within facilities. The MHDO is developing data elements that will allow an individual to be more reliably tracked both across time within a given facility and between facilities. MHDO plans consider a Rule Change to add patient SSN, patient name and patient street address to Chapter 241 Uniform Reporting System for Hospital Inpatient Data Sets and Hospital Outpatient Data Sets in 2017-2018 with an effective date of 2019.

Q. What Diagnosis Related Group (DRG) information is available in the Inpatient data.

A. MHDO assigns DRGs using the 3M Grouper software. Currently, two different sets of DRG codes and Major Diagnostic Categories (MDC) codes are created: one based on the All Patients Refined Diagnosis Related Groups (APR-DRG) and the other on the Medicare Severity-Diagnosis Related Groups (MS-DRG). The MDHO had previously also distributed two older versions of DRGs (AP-DRGS and CMS-DRGs) which have since been depreciated by their maintainers.
Both the APR-DRG and the MS-DRG are revised annually. The version of the DRGs used for records with discharge dates before 10/1/2015 was 32.0; the version used for records on or after this date was 33.0.

Q. What diagnosis fields are available in the current Rule Chapter 241 layout for the Hospital data?

A. In the current version of Rule Chapter 241, amended on November 22, 2015 the diagnosis fields that are available are Version 040 which has one principal diagnosis, one admitting diagnosis code, two external injury codes, and eight other diagnosis codes (ICD-9); the versions 050 and 060 layout has one principal diagnosis code, one admitting diagnosis code, two external injury codes, and eight other diagnosis codes (ICD-10). Note: ICD-9 and ICD-10 data elements are stored in different fields. For instance, the ICD-9 principal diagnosis is stored in the field IP7004_PrincipalDiagnosisCode while the ICD-10 version is stored in IP7104_PrincipalDiagnosis. Whenever possible, data elements are prefixed with the data element name from the input layout specified in Rule Chapter 241, Uniform Reporting System for Hospital Inpatient Data Sets and Hospital Outpatient Data Sets, which provides additional details on the derivation of each element in Appendix B-2.

Q. Does the Hospital data include uninsured patients’ diagnoses? In other words, would the uninsured patients’ data be the same as all other patients’ data except that there would be no payment information?

A. Yes, services rendered to the uninsured are reported in the Hospital Inpatient and Outpatient data. Patients with no insurance appear with “self-pay” indicated as the primary “payer.” Note: The hospital encounter data releases exclude all financial data.

Q. Should I see a procedure code on all Inpatient admissions?

A. No, the service lines where procedures codes are missing are what we would expect to see – for example medical sub-service lines (medical cardiology, medical orthopedics and spine, etc.).

Q. Why do some hospitals have high rates of self-pay for pay2 and pay3 fields?

A. There are two hospitals that have confirmed that their system defaults to self-pay in the payer fields after all validated insurance carriers are included