The CDC has posted a study collecting vast amounts of data on 2004 emergency department visits in hospitals across the country.  While there are no big surprises here — patients are triaged and seen according to severity of illness/injury, there are fewer EDs than there used to be, Medicaid and SCHIP beneficiaries tend to use the ED more than others — this study provides a detailed baseline which may be used in future studies to plan and evaluate modifications to the prehospital and ED care systems.