Accuracy of Staff-Initiated Emergency Department Tracking System Timestamps in Identifying Actual Event Times - 21/08/11

Doi : 10.1016/j.annemergmed.2007.11.036

Bradley D. Gordon, MD, MS ^a,^b,^⁎ , Thomas J. Flottemesch, PhD ^a, Brent R. Asplin, MD, MPH ^a,^b
^a Regions Hospital Department of Emergency Medicine, St. Paul, MN, and the HealthPartners Research Foundation, Bloomington, MN
^b Department of Emergency Medicine, University of Minnesota Medical School, Minneapolis, MN

Address for correspondence: Bradley D. Gordon, MD, MS, Regions Hospital, Mailstop 11102F, 640 Jackson Street, St. Paul, MN 55101; 651-254-6994, fax 651-254-5216

Résumé

Study objective

Managers use timestamps from computerized tracking systems to evaluate emergency department (ED) processes. This study was designed to determine how accurately these timestamps reflect the actual ED events they purport to represent.

Methods

An observer manually timestamped patient and provider movement events during all hours. The observed timestamps were then systematically matched to equivalent timestamps collected by an active tracking system (timestamps created by staff with keyboard/mouse) and a passive tracking system (timestamps created by sensor badge worn by staff members). The deviation intervals between the matched timestamps were analyzed.

Results

The observer noted a total of 901 events; 686 (76%) of these were successfully matched to active system timestamps and 60 (6.7%) were matched to passive system timestamps. For the active system, the median event was recorded 1.8 minutes before it was observed (interquartile range 30.7 minutes before to 2.9 minutes after). Protocol execution difficulties limited the study of the passive system (low number of successfully matched events). The median event was recorded by the passive system 1.1 minutes before it was observed (interquartile range 1.3 minutes before to 0.9 minutes before) (n=60).

Conclusion

The timestamps recorded by both active and passive tracking systems contain systematic errors and nonnormal distributions. The active system had much lower precision than the passive system but similar accuracy when large numbers of active system observations were used. Medians should be used to represent timestamp and interval data for reporting purposes. Site-specific data validation should be performed before use of data in high-profile situations.

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Plan

Introduction

Background

Importance

Goals of This Investigation

Materials and Methods

Study Design

Setting

Data Collection and Processing

Primary Data Analysis

	Author contributions: All authors are responsible for study conceptualization and design. BDG coordinated data acquisition, drafted the article, obtained funding and supervised of the study execution. BDG and TJF performed analysis and interpretation of the data. TJF provided detailed statistical support. All authors contributed substantially to the intellectual content and critical revisions of the paper. BDG takes responsibility for the paper as a whole.
	Supervising editor: Robert L. Wears, MD, MS
	Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article, that might create any potential conflict of interest. See the Manuscript Submission Agreement in this issue for examples of specific conflicts covered by this statement. Dr. Gordon is supported by a National Library of Medicine Early Career Development Award in Medical Informatics (K22LM008573-01).
	Reprints not available from the authors.
	Publication date: Available online March 7, 2008.