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Patient Migration

An example of patient migration is: for residents of the Barre hospital service area, what can we conclude about where they go for care? Does that change over time?

Patient Migration      (Interactive Report)

The Patient Migration report is an annual report based on the resident perspective, i.e. where the patient is going for care. VAHHS-NSO has produced another, separate report covering the provider perspective, which describes where patients travel from for care. This second, separate report is the Hospital Market Report.

The data presented are based on administrative claims for most of Vermont's insured population. To report on patient migration at the population level, we use the hospital service area of residence and primary insurance type as these have the greatest impact on migration. The summary file is created by aggregating total spend for every patient, month of eligibility, payer, HSA of residence, and HSA of care. Note, within this data structure, patients can live in more than one area in the year and month. We allow these multiples over time because this most accurately represents the complete migration of populations. Also note, this report includes all provider types and all services within the HSA, not just those occurring at the hospitals.

Additional limitations and specifications are listed below:

Claims Included

  • This version of the report focuses on medical claims only. Although previous versions incorporated pharmacy expenditures, further exploration of this data is needed to accurately depict utilization and cost.
  • This version expands on previous work to add "Care Type," a variable which identifies if the claims are for care received in an inpatient facility setting (UB-04 claims), outpatient facility setting (UB-04 claims, includes ER claims), professional office setting (CMS-1500 claims), or other (durable medical equipment, hospice, home health, or unclassified).


  • Not all medical expenditures are captured on insurance claims. For example, capitated arrangements between insurers and providers, some case management payments, and pharmacy rebate payments are all examples of important areas of health care spending that are not included in claims.
  • We include fee-for-service (FFS) equivalent expenditures for Medicare beneficiaries attributed to an Accountable Care Organization (ACO) to replicate Medicare's own methodology for calculating total expenditures. Medicaid FFS equivalences are excluded because the prospective payments are not reconciled to claims-level expenditures. As a result, this analysis underestimates the total spending associated with Medicaid beneficiaries aligned to an ACO.
  • Total Medical Expenditures or Total Medical Spend are calculated by taking the sum of the insurance payment, the expected member coinsurance, copay, deductible, and for Medicare, includes the FFS equivalents.

Claims Run Out

  • We include claims with dates of service in years 2017 through 2022.
  • This version of the report uses VHCURES extract 3008, with incurred claims through 12/31/2022 and paid through 3/31/2023. Medicare incurred through 12/31/2022 and paid through 3/31/2023.