title: Geographic information software programs' accuracy for interfacility air transport distances and time.
abstract: BACKGROUND
  This study aimed to evaluate consistency/predictability of interfacility flight times (IFFTs) and accuracy of geographical information system (GIS) software packages for estimating IFFT.
  
  
  METHODS
  This retrospective study conducted by a program using a Bell 206 assessed the first 1000 IF transports occurring on 137 "runs" (ie, referring-receiving hospital pairings) made at least twice. GIS IFFT estimates using Google Earth™ (GE) and ArcGIS™ (AG) were compared against actual IFFT using linear regression; univariate analysis included assessment of medians with 95% binomial exact confidence intervals (CIs). Interrater agreement for GIS was assessed with κ.
  
  
  RESULTS
  GE and AG estimates fell, respectively, within 1 mile of actual in 136/137 runs (99%, 95% CI 96%-100%) and 130/137 runs (95%, 95% CI 90%-98%). GE- and AG-predicted IFFT strongly (P < .001) correlated with, underestimating by about 2 minutes, actual IFFT (GE: r2 0.93, coefficient 0.98, 95% CI .97-1.00; AG: r2 0.93; coefficient 0.98, 95% CI .96-1.0). GE and AG had statistically equivalent (κ > .8), "almost-perfect," interrater agreement.
  
  
  CONCLUSIONS
  IFFTs for same-run helicopter EMS transports in our rural state setting are characterized by little variability. GIS is highly accurate in predicting IF logistics, with public-domain GE performing as well as more expensive AG.
authors: Department of Emergency Medicine, University of Oklahoma College of Medicine, Tulsa, OK, USA.
authors: Jaron J
authors: JJ
authors: Soulek
authors: Department of Emergency Medicine, University of Oklahoma College of Medicine, Tulsa, OK, USA. Electronic address: Annette-Arthur@OUHSC.edu.
authors: Annette O
authors: AO
authors: Arthur
authors: Department of Emergency Medicine, University of Oklahoma College of Medicine, Tulsa, OK, USA.
authors: Emily
authors: E
authors: Williams
authors: Department of Emergency Medicine, University of Oklahoma College of Medicine, Tulsa, OK, USA.
authors: Christoph
authors: C
authors: Schieche
authors: AirEvac Lifeteam, O'Fallon, MO, USA.
authors: Noah
authors: N
authors: Banister
authors: Department of Emergency Medicine, University of Oklahoma College of Medicine, Tulsa, OK, USA; AirEvac Lifeteam, O'Fallon, MO, USA; The Center for Medical Transport Research, Columbus, OH, USA.
authors: Stephen H
authors: SH
authors: Thomas
mesh_terms: D017732:Air Ambulances; D040362:Geographic Information Systems; D006801:Humans; D015588:Observer Variation; D012189:Retrospective Studies; D012984:Software; D013997:Time Factors