As dementia progresses and cognitive function declines, surrogate decision making becomes increasingly prevalent. By convention, there is a hierarchical approach to proxy decision making beginning with known wishes, followed by a substituted judgment standard, and then a best-interests standard. For people with dementia, discrepancy in proxy assessments is common and associated with negative behavioral outcomes. Therefore, optimal approaches to proxy decision making for people with dementia should instead prioritize and implement options that encourage direct participation of persons with dementia and standards that explicitly rely on consideration of longitudinal changes in values and preferences for persons with dementia.