How are Emergency Room wait times calculated? Emergency Room wait times represent the average estimated length of time from registration to being assigned a "first provider" (a doctor, nurse practitioner or physician assistant). The wait times displayed on this site are refreshed at least every 10 minutes. Many circumstances can affect wait times – for example, patients arriving by ambulance or with life-threatening injuries or illnesses. Patients with life-threatening conditions will be seen before those with less-serious problems or ailments. These times are provided for informational purposes only and cannot be guaranteed upon arrival. They may be subject to change without notice.