Preference measurement

In the PHI, a health state represents one stage in the progression or treatment of a disease. A numeric value, sometimes called a weight or a preference score, needs to be assigned to various health states as a measure of morbidity. This score represents an individual’s relative preference for a health state compared with full health. It can be combined with epidemiological data to estimate the morbidity associated with that disease.

We elicited preference scores from 17 panels of Canadians, each with about 10 participants. Participants considered how the limitations of various health states (described using the attributes in CLAMES) would affect their own lives in terms of usual activities, such as work, school, community participation and social roles. They gave each health state a score reflecting their relative preference for it compared with full health. The standard gamble method was used in these exercises because it is grounded in utility theory and participants in focus groups preferred it to other techniques (e.g., time trade-off, person trade-off).

Median scores from this exercise will be used to reflect the population’s relative preference for about 200 health states on a numeric scale. A statistical function will then be derived to estimate preference scores for another 200 health states that were not directly measured in the field.

A future issue of this newsletter will describe these measurement exercises and provide some preliminary results.

Sarah Gorber