Measuring locomotor disability: a new scoring mechanism for some familiar items
- Arthritis Research Campaign National Primary Care Centre, Primary Care Sciences, Keele University, Keele, Staffordshire, UK
Background
Locomotor disability is a critical measure for studying functional decline in later life and has featured in several major epidemiological studies. Yet measurement has mostly been confined to single items or ordinal scales rather than truly unidimensional measures with interval properties, thereby limiting the detection and interpretation of change in locomotor disability over time. Our aim was to combine items from the well-known SF-36 Physical Functioning Scale (PF-10) into a single score using Rasch analysis and test the properties …
