title: Posted emergency department wait times are not always accurate.
abstract: OBJECTIVE
  Hospitals around the United States are advertising emergency department (ED) wait times. The objective was to measure the difference between publicly posted and actual ED wait times and to compare these between ED site volumes.
  
  
  METHODS
  This study was a retrospective consecutive sample of ED patients at one hospital system with four EDs. The wait times of 8,889 patients were included in this analysis. One ED was in a large teaching hospital with 5,000 ED patients per month; the other three were freestanding or community EDs without teaching and with fewer than 2,000 ED patients per month each. The publicly posted ED wait times at the time of patient arrival were recorded and compared to the actual wait times as retrieved from the ED tracking system. The difference between posted and actual wait times for each site was calculated. Separate one-way analysis of variance (ANOVA) tests with post hoc testing were conducted to assess actual wait time and wait time difference between ED sites.
  
  
  RESULTS
  Mean and standard deviation (SD) wait time difference at the main ED with a volume of 5,000 patients per month was 31.5 (±61.2) minutes. At the facilities with fewer than 2,000 ED patients per month each, the differences in wait times were 4.2 (±21.8), 8.6 (±23.8), and 1.3 (±11.9) minutes. ANOVA results revealed that the main ED had significantly different actual wait time and wait time differences (p < 0.05) when compared to the other three EDs.
  
  
  CONCLUSIONS
  In one hospital system, publicly posted ED wait times show better accuracy in EDs that see 2,000 or fewer patients per month and less accuracy for an ED that sees 5,000 patients per month, likely due to flow confounders.
authors.affiliation: Department of Emergency Medicine, Department of Internal Medicine, Akron General Medical Center, Akron, OH, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Jouriles
authors.forename: Erin L
authors.initials: EL
authors.lastname: Simon
authors.forename: Peter
authors.initials: P
authors.lastname: Griffin
authors.forename: Carolyn Jo
authors.initials: CJ
authors.lastname: Williams
authors.forename: Nairmeen Awad
authors.initials: NA
authors.lastname: Haller
mesh_terms: D000704:Analysis of Variance; D061827:Dimensional Measurement Accuracy; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D006764:Hospitals, Community / Q000706:statistics & numerical data*; D006784:Hospitals, Teaching / Q000706:statistics & numerical data*; D006801:Humans; D012189:Retrospective Studies; D013997:Time Factors; D014481:United States; D014850:Waiting Lists