'Disability' is defined by Statistics New Zealand as: any self-perceived limitation in activity resulting from a long-term condition or health problem; lasting or expected to last six months or more and not completely eliminated by an assistive device.

'Serious disability' is defined by Statistics New Zealand as: any self-perceived limitation in activity resulting from a long-term condition or health problem; lasting or expected to last six months or more and not completely eliminated by an assistive device.