Background Differentiating between appropriate and inappropriate resource use represents a critical challenge in health services research. The New York University Emergency Department (NYU ED) visit severity algorithm attempts to classify visits to the ED based on diagnosis, but it has not been formally validated. Objective To assess the validity of the NYU algorithm. Research Design: A longitudinal study in a single integrated delivery system (IDS) from January 1999 to December 2001. Subjects 2,257,445 commercial and 261,091 Medicare members of an IDS. Measures ED visits were classified as emergent, non-emergent, or intermediate severity, using the NYU ED algorithm. We examined the relationship between visit-severity and the probability of future hospitalizations and death using a logistic model with a general estimating equation (GEE) approach. Results Among commercially insured subjects, ED visits categorized as emergent were significantly more likely to result in a hospitalization within one-day (OR=3.37, 95% CI: 3.31–3.44) or death within 30-days (OR=2.81, 95% CI: 2.62–3.00) than visits categorized as non-emergent. We found similar results in Medicare patients and in sensitivity analyses using different probability thresholds. ED overuse for non-emergent conditions was not related to socio-economic status or insurance type. Conclusions The evidence presented supports the validity of the NYU ED visit severity algorithm for differentiating ED visits based on need for hospitalization and/or mortality risk; therefore, it can contribute to evidence-based policies aimed at reducing the use of the ED for non-emergencies.

The examination room computers appeared to have positive effects on physician-patient interactions related to medical communication without significant negative effects on other areas such as time available for patient concerns. Further study is needed to better understand HIT use during outpatient visits.