BACKGROUND:Little is known about the factors that influence physicians' admission decisions, especially among lower acuity patients. For the purpose of our study, non-medical refers to all of the factors-other than the patient's clinical condition-that could potentially influence admission decisions. OBJECTIVE: To describe the influence of non-medical factors on physicians' decisions to admit non-critically ill patients presenting to the ED. DESIGN: Cross-sectional study of hospital admissions at a single academic medical center. PARTICIPANTS: Non-critically ill adult patients admitted to the hospital (n=297) and the admitting emergency medicine physicians (n=34). MAIN MEASURES: A patient survey assessed nonmedical factors, including primary care access and utilization. A physician survey assessed clinical and nonmedical factors influencing the decision to admit. Based on physician responses, admissions were characterized as Bstrongly acuity-driven,^Bmoderately acuity-driven,ô r Bweakly acuity-driven.^Among these admission types, we compared length of stay, cost, and readmission within 30 days to the hospital or ED. KEY RESULTS: Based on the admitting physician's assessment, we categorized the motivation for admission as strongly acuity-driven in 185 (62 %) admissions, moderately acuity-driven in 92 (31 %), and weakly acuity-driven in 20 (7 %). Per the physician surveys, 51 % of hospitalizations were strongly or moderately influenced by one or more non-medical factors, including lack of information about baseline conditions (23 %); inadequate access to outpatient specialty care (14 %); need for a diagnostic testing or procedure (12 %); a recent ED visit (11 %); and inadequate access to primary care (10 %). Compared with strongly-acuity driven admissions, admissions that were moderately or weakly acuity-driven were shorter and less costly but were associated with similar rates of ED (35 %) and hospital (27 %) readmission. CONCLUSIONS: Non-medical factors are influential in the admission decisions for many patients presenting to the emergency department. Moderately and weakly acuity-driven admissions may represent a feasible target for alternative care pathways.KEY WORDS: non-medical factors; hospital admission decision; access to care; care transitions; decision making; emergency medicine; health care delivery; medical decision making; severity of illness; socioeconomic factors; utilization.