Care Doesn’t Always Stay Connected

A micro-field note on continuity, interruption, and what longitudinal evidence requires

Longitudinal data helps medicine understand what happens over time—but only when patients remain connected to care, and the populations observed reflect real-world diversity. This micro Field Note examines how continuity and access shape what becomes evidence.

Some of the most important medical insights we have exist because patients were followed over time.

We understand long-term cardiovascular risk in part because studies like Framingham tracked participants across decades.
We know many cancers recur years later because patients remained connected to care long enough for those patterns to be observed.

But longitudinal evidence only exists when people stay connected to care. And care does not always stay connected.

People:
switch providers
lose coverage
miss follow-up
move
start over

The timeline continues. The record fragments.
Many gaps in evidence begin there—before the dataset ever exists. But continuity alone does not make evidence complete. Who remains connected to care also shapes what b…