1.Describe the process for evaluating the reliability, validity, and clinical utility of a pain assessment instrument in noncommunicative palliative care patients.2.Articulate the potential clinical uses of a pain assessment instrument for noncommunicative palliative care patients. Background. Assessing pain in acutely ill palliative care patients who cannot self-report remains a major clinical challenge. Researchers have developed behavioral and physiologic measures for such patients, but focused on single settings with patients having varying levels of cognitive impairment and self-report capability. Our multisite study evaluates the reliability, validity, and clinical utility of the MOPAT, an objective behavioral (BEH) and physiologic (PHY) measure of acute pain in noncommunicative patients in two settings’ acute care hospital and hospice inpatient unit. Research objectives. The purpose of this presentation is to report reliability, validity, and clinical utility data from the acute care setting. Methods. The study used a cross-sectional instrument-testing design with pain ratings before and after a pain-relieving intervention. The sample was comprised of 163 hospitalized palliative care patients with painful conditions who could not self-report any aspect of their pain. Independent MOPAT ratings before and after the intervention was performed by two study nurses (SNs) or by a SN and volunteer staff nurse (VSN). VSNs completed a Clinical Utility Questionnaire (CUQ) monthly during the study. Results. Preliminary analysis indicates that percent agreement between rater pairs was 72.3-86.6 for SN/SN and 69.4-84.5 for SN/VSN on the BEH subscale, and 78.4-81.3 for SN/SN and 74.4–79.9 for SN/VSN on the PHY subscale. Internal consistency reliability differed by whether patients were able to vocalize sounds or not, with higher alpha coefficients on BEH for those able to vocalize (0.84). VSNs had positive perceptions of the MOPAT, with higher CUQ scores if completed within 30 days of MOPAT use. Conclusion. The preliminary analysis suggests that the MOPAT performed reasonably well. More in-depth psychometric and clinical utility analyses are underway. Implications for research, policy, or practice. A psychometrically sound and clinically useful objective measure of acute pain may help in assessing pain in noncommunicative palliative care patients across settings.