~ SharpC at Maryland ~

Twinlist (and more):
Novel User Interface Design for
Medication Reconciliation

twinlist layout
From 2 lists side by side to . . .     to the Twinlist layout      
twinlist more complex case twinlist aligned by diagnosis twinlist with selections
A more complex case            Aligned by diagnosis               With selections      

Scroll to find the VIDEOS and open source software

Maryland Participants

  • Catherine Plaisant, (Co-PI) - Research Scientist, UMIACS, Associate Director of Research at HCIL
  • Ben Shneiderman, (Co-PI) - Professor, Computer Science, Researcher (and Founding Director) at HCIL
  • (past) Tiffany Chao, Graduate Student in the Department of Computer Science, University of Maryland
  • (past) Johnny Wu, Graduate Student in the Department of Computer Science, University of Maryland

Other Participants

  • University of Texas, Houston: Todd Johnson, Jorge Herskovic, Elmer V Bernstam, Eliz Markovitz (and many more providing feedback)
  • Yale University: Seth Powsner
  • Medstar Institute for Innovation: Zach Hettinger


  • June 2015: Story on our Twinlist prototype for medication reconciliation appears in User Experience, the Magazine of the User Experience Professionals Association.
  • Nov. 2014: Twinlist evaluation paper accepted at JAMIA
  • June 2014: New eBook Inspired EHRs: Designing for Clinicians , an eBook for developers of Electronic Health Record systems released. You will find clinical scenarios, designs, interactive prototypes, and introductory materials on human factors, design and usability. Includes a chapter on Medication reconciliation, which reviews Twinlist - and other designs
  • >>>>Nov 2013: Twinlist paper received Distinguished Paper Award at AMIA 2013<<<<


The University of Maryland is one of the nine institutions participating in the National Center for Cognitive Informatics and Decision Making in Healthcare (NCCD) led by The University of Texas Health Science Center at Houston. NCCD is funded by the Office of the National Coordinator for Health IT under the Strategic Health IT Advanced Research Projects (SHARP) Program. This program seeks to support improvements in the quality, safety and efficiency of health care through advanced information technology. The NCCD award was one of four presented by the Office of the National Coordinator for Health Information Technology (ONC) through the American Recovery and Reinvestment Act of 2009 to address key barriers to health information technology. NCCD's research focus area is Patient-Centered Cognitive Support.

For more information see:
1) the NCCD website at the University of Texas in Houston (the main PI) OR
2) the Maryland webpage which provides a summary of all the SharpC projects HCIL participated in.

Project Description

Medication reconciliation is an important and complex task for which careful user interface design has the potential to help reduce errors and improve quality of care. In this project we focused on the inpatient situation: a clinician is in the process of discharging a patient from the hospital and needs to compare the list of home medications with the medications dispensed at the hospital and decide what the patient should take when he/she returns home.

The main output of this project is a novel interface called Twinlist, which illustrates the use of spatial layout and multi-step animation, to help medical providers see what is different and what is similar between the lists (e.g. intake and hospital lists), and rapidly select the drugs they want to include in the reconciled list.

Other prototypes were designed to present alternative user interfaces: variations on the Twinlist interface, and an interface called Medrec developed by our collaborators at Houston.

Those interfaces were built on the substratum of a novel medication reconciliation algorithm that computes the similarity between drugs. That similarity information can then be presented to the clinician by the user interface, and remove the tediousness of a fully manual reconciliation without diminishing the decision making power of the clinician.

The basic design of Twinlist can be adapted to other reconciliation tasks such as problem reconciliation or allergy reconciliation.



  • INTRODUCTION TO TWINLIST (visual layout and animation help users see similarities, simple interaction allows rapid selection):
    Start by watching this
    Watch it on YouTube: URL: http://www.youtube.com/watch?v=YXkq9hQppOw
    or stream/download our mp4 version (22.6 MB, 1024 x 768 resolution, 2:11 min.)


    Watch it on YouTube: URL:www.youtube.com/watch?v=dABfksDvOiw
    or stream/download our mp4 version the video (35.3 MB, 1024 x 700 resolution, 9:18 min.)
    See exactly what participants used with Twinlist with a baseline interface (for the results see our paper above)
    Stream/download our mp4 version (18.8 MB, 1280x800 resolution, 5:41 min.)
  • ALTERNATIVE INTERFACE: MEDREC - from U. of Texas Houston
    (example with mobile device, with drag and drop interaction)
    [From our SharpC Project 4 partners] Contact: Jorge R. Herskovic.

    Watch it on YouTube:


    Watch it on YouTube:
    For more info see the MANYLISTS project page

Open Source Software

Lectures Slides (sample)

Related projects


This work is supported in part by Grant No. 10510592 for Patient-Centered Cognitive Support under the Strategic Health IT Advanced Research Projects Program (SHARP) from the Office of the National Coordinator for Health Information Technology.

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