Identity, the view of self-reference, is not static across populations and is probably not stable within an individual over time. Philosophers, psychologists and the religious continue to offer support for particular points of view of identity but there are many differences among them. These differences seem quite able to bias utility and patient-reported outcomes assessments. As such, care must be taken to understand the self-reference schemas of the population within which self-assessments are validated and used. Some of the options people have and use for self-reference are: 1. operational (e.g., I am a clinical researcher or a father), 2. preference-oriented (e.g., I am a lover of wine or a “runner”), 3. physical (e.g., I am my body), 4. psychological (e.g., I am my ego), 5. religious (e.g., I am spirit) and 6. philosophical (e.g., I am thinking, I am consciousness, no such thing as identity exists, I am subjective experience). It's surprising self-assessments are conducted when we don't know who is responding to our questions. The confound of identity is important to study in its own right because of how strongly it can influence public policy through research findings based on self-assessments. “View of self-reference” seems a fundamental and necessary element for inclusion into requirements for construction and validation of PROs. Otherwise, instrument bias could be specifically used to make a certain claim, much like regression towards the mean could be used if it was not previously identified as a threat to validity. That identify may shift over time within an individual, say from an external focus to an internal focus, may be the reason why some terminally ill patients report good quality of life despite their poor health. When the body is not a factor in one's identity, what is the meaningfulness of health-related quality of life anyway?