ABSTRACT The National Academy of Medicine and the National Institutes of Health have called for urgent action to improve the care delivered to the nearly 1,000,000 elderly Americans who die in intensive care units (ICUs) annually, or survive with severe disabilities. The problems include: 1) patients with a poor prognosis often receive more invasive, burdensome treatment than they would choose for themselves; 2) family members acting as surrogate decision-makers find the experience emotionally overwhelming and suffer lasting psychological distress; and 3) treatment in ICUs contributes to high end-of-life health care costs. These problems are especially important to elderly patients, whose willingness to undergo invasive, life-prolonging treatments varies and hinges on highly personal values and preferences. Despite widespread recognition of these problems, there are no readily-scalable interventions that are proven effective to assist surrogates in ICUs. Over the last 3 years (R21AG050252), we used a multi-stakeholder process to first develop, then iteratively refine the Family Support Tool, an interactive, web-based tool to help family members of elderly, incapacitated patients navigate the emotional, psychological, and cognitive complexities of being a surrogate decision-maker. We then established in a single-center RCT that the intervention is feasible, acceptable, improves the quality of clinician- family communication, and is perceived to be highly beneficial by surrogates in ICUs. We propose to conduct an appropriately powered randomized clinical trial of the Family Support Tool among the surrogates of 450 elderly, critically ill patients at high risk of death or severe disability. In Aims 1 and 2, we will determine the effect of the Family Support Tool on patients’ clinical outcomes, surrogates’ psychological outcomes, measures of decision quality, and end- of-life healthcare utilization. In Aim 3, we will conduct a qualitative study in parallel with the RCT to identify the contextual factors, barriers, and facilitators that may influence the efficacy of the Family Support Tool. The research is highly significant because it will establish the efficacy of a low-cost, scalable intervention to overcome major public health problems that affect hundreds of thousands of Americans annually. This proposal is innovative because the intervention challenges the existing paradigm of how to support surrogates facing difficult decisions near the end of life. The work is feasible in our hands because our team of established investigators successfully developed and pilot tested the Family Support Tool, has a proven record of success conducting trials in ICUs, and has buy-in for participation from all sites.