Why are we weighting? A critical examination of the use of item weights in a health status measure.

There is currently much interest in the measurement of self reported health status. A number of health status measures have been designed. However, such questionnaires are often long and complicated, or are disease specific. The most famous generic British health status instrument is the Nottingham Health Profile (NHP) which is a short questionnaire designed for ease of completion. However, this paper addresses a number of related issues concerning the weights attached to particular items on this questionnaire. It is argued that the weighting of items by Thurstone's method of paired comparisons is inappropriate and can lead to logically inconsistent results.