Medical technologies, nonhuman aids, human assistance, and environmental factors in the assessment of health states.

Researchers have developed various health state measures to capture the value of living well. They have reached a consensus that health state measures focus on functionality and general symptoms. One can assess functionality and general symptoms with or without medical technologies (for example, medication, laser surgery, or a pacemaker), nonhuman aids (for example, glasses or a wheelchair), human assistance (for example, the help of another person), and accommodating environmental factors (for example, a barrier-free physical environment). Researchers have paid little attention to these distinctions. In this paper, I discuss why such distinctions are important and explore what implications they have for the construction and application of health state measures. I use the Health Utilities Index Mark 3 (HUI) and the health state measure in the World Health Survey (WHS) as examples of pioneer measures that explicitly acknowledge different levels of functionality and general symptoms. I conclude that the inclusion of medical technologies and nonhuman aids in the assessment of health is reasonable, but not human assistance or accommodating environmental factors. While this conclusion is in line with the HUI and WHS, I discuss a rationale for this boundary and make further suggestions regarding scoring of health states.