Joint stiffness (pooled across scales)

Method

Standardised mean difference for self-reported joint stiffness pooled across trials in which the source instrument was not held constant; the pooled estimate names no single instrument.

The method is part of the endpoint identity. Studies measuring the same quantity by a different method are held as separate endpoints.

Notes

Exists only because the pooled estimate has no native scale. Most of the underlying data come from the WOMAC stiffness subscale, which is recorded separately in its own score units; a dimensionless SMD and a native subscale score cannot share a node without destroying the scale on one side. Also distinct from morning-stiffness DURATION in minutes, a different construct measured in clock time and frequently reported under the same word.