The Brief Interview for Mental Status (BIMS) is used to identify delirium and needed supports in patients living in skilled nursing facilities (SNFs) and long-term care facilities (LTCFs). We analyzed 3,537,404 patients discharged from acute hospitals to SNFs or LTCFs with factor and Rasch analyses to examine the clinical utility of the BIMS. More than 40% of the sample had maximum scores, indicating a ceiling effect. "Repetition of three words" was the easiest and the only misfit item (Outfit = 3.14). The ability of the BIMS to distinguish individuals into two cognitive levels (with person strata of 1.48) was limited. Although the BIMS is a widely used screening tool for cognitive impairment, we found it lacked sensitivity for approximately one half of patients admitted to SNFs/LTCFs. Our results suggest the BIMS should be interpreted with caution, particularly for patients with mild cognitive impairment. [Research in Gerontological Nursing, 15(3), 124-130.].