The patient the model does not see.

The QALY combines length of life and health-related quality of life in a common measure. It allows comparison between outcomes that would otherwise be difficult to place on the same scale. This is a valuable analytical possibility.

The problem begins when a useful measure is asked to exhaust our judgement. An aggregate result, on its own, says little about the distribution of benefits, people’s starting conditions or the barriers they face in accessing a service.

In NICE’s methodological reference for guidelines, a QALY carries equal weight across groups. This makes a convention explicit. It does not settle every question of equity: it places them alongside the calculation, where they can be discussed.

A spreadsheet does not necessarily hide people. It can make their needs visible, especially those pushed to the margins by the story of an individual case. But doing so requires us to know which differences we have chosen to represent and which we have compressed into an average.

The criticism we need enters the model, reads its assumptions and comes out with more precise questions. Who gains health? Who remains excluded? Which difference disappears when we present only the total?