Coverage is universal from day one and never partial. What improves over time is the distribution of travel times — a mean, a spread and a tail — moved down by density and staffing. A distribution has no completion state, so access is never reported as a percentage complete. It is measured by condition and time to definitive care, and its honest milestone is the crossover year when as many sites open as close: net-negative today, and plausibly a twenty-year horizon. This clock runs separately from the transition, and for longer.
One rule does the work of several. Universal assignment ends deserts by definition: a desert county is one no system wants, and under universal assignment there is no such thing as an unwanted county — only a county whose assignment carries a capacity payment.
It is also the anti-dumping mechanism, because an Authority with a standing catchment obligation cannot improve its position by moving a patient out. And it crosses state lines without machinery, because the charter is federal.
Existing health systems have catchments with edges, and the edges are not arbitrary — they are where the payer mix stops supporting the service. A system extends into an affluent suburb and stops before a rural county, and under fee-for-service both decisions are rational.
So deserts are not unreachable. They are *unattractive*, and unattractive for a reason the payment method creates. That is the same finding as the ambulance desert: not a funding shortfall but a payment design with no line for the thing being bought.
Which means deserts can be **attached rather than built**, provided the attachment is funded — a materially simpler programme than chartering new institutions in every underserved county.
Assignment is county by county on four criteria. Observed referral flow, answerable from claims data, and it should govern rather than political boundaries. Drive time to the nearest capable receiving centre, by service line and by season. Existing institutional relationships. And Authority scale — a catchment too small to carry management overhead is merged, one too large to govern is split.
Assignment is published, appealable by county government, and reviewed on a fixed cycle. Where flow is genuinely split, a county may be assigned to one Authority for emergency and obstetric care and another for oncology. Splitting by service line is normal in regionalized systems.
Attachment brings funding with it: capacity payment for standing capability inside the county, retrieval network funding on the ground and in the air, a share of the receiving centre's tele-support budget, and an access-distribution reporting obligation.
The Authority does not take on an unfunded burden. It takes on a funded obligation, and that is the whole difference from the present arrangement.
Trauma systems already assign by designated region, and Medicare's referral regions cover the country without gaps. Universal assignment is not a novel administrative form.
Assigning counties creates winners and losers among incumbent systems, and the criteria will be lobbied.
Publishing the referral-flow data that drives assignment is the defence. An assignment that departs from observed flow has to be justified in public against the claims record, which is a materially harder thing to lobby for than a closed-door boundary.
Honesty about gaps. Distributed Healthcare has more unresolved specification than other Engines because operational complexity is higher; the items below are flagged for v10.2 specification or for outside expert review.
- Whether catchments may split by service line is recommended but not ruled.