Paper presentation at the ACM SIGCHI Conference on Human Factors in Computing Systems (CHI). Vancouver, BC (May 10, 2011) More info: http://www.cs.umd.edu/hcil/lifeflow Abstract: Event sequence analysis is an important task in many domains: medical researchers may study the patterns of transfers within the hospital for quality control; transportation experts may study accident response logs to identify best practices. In many cases they deal with thousands of records. While previous research has focused on searching and browsing, overview tasks are often overlooked. We introduce a novel interactive visual overview of event sequences called LifeFlow. LifeFlow is scalable, can summarize all possible sequences, and represents the temporal spacing of the events within sequences. Two case studies with healthcare and transportation domain experts are presented to illustrate the usefulness of LifeFlow. A user study with ten participants confirmed that after 15 minutes of training novice users were able to rapidly answer questions about the prevalence and temporal characteristics of sequences, find anomalies, and gain significant insight from the data.

1. LifeFlow:Visualizing an Overview of Event Sequences by Krist Wongsuphasawat
is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

2. event
event event
event event
event
event
event
LIFE event
event
event
event
event event
event
event
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

3. Time Event type
( 7:00 am, Wake up )
event
event event
event event
event
event
event
LIFE event
event
event
event
event event
event
event
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

4. event
event event
event event
event
event
event
LIFE event
event
event
event
event event
event
event
“Event Sequence”
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

5. Human Activities
( 7:00 am, Wake up ) ( 7:10 am, Shower ) ( 7:30 am, Breakfast )
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

6. Traffic Incidents Logs
( 9:30 am, Notification ) ( 9:55 am, Units arrived) ( 10:30 am, Scene cleared )
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

7. Event Sequences
Human Activities
Electronic Health Records
Traffic Incident Logs
Usability Study Logs
Web logs
and more…
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

8. Physicians at
Washington Hospital Center
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

9. Electronic Health Records
• E.g. patient transfers in the hospital
• Event types:
ARRIVAL Arrive the hospital
EMERGENCY Emergency room
ICU Intensive Care Unit
FLOOR Normal room
DISCHARGE-ALIVE Leave the hospital alive
DIE Leave the hospital dead
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

10. Improve the Quality of Care
Patient ID: 45851733
Patient ID: 45851732
12/02/2008
14:26
Arrival
Emergency Department
12/02/2008
14:26ID:Arrival
12/02/2008
14:26
45851731
Patient
Emergency
6,000+
12/02/2008
22:44
ICU
mergency
12/02/2008
14:26
E
12/05/2008
05:071Floor
Arrival
12/02/2008
4:26
12/02/2008
22:44
ICU
mergency
12/02/2008
14:26
E
12/08/2008
10:02
Floor
12/05/2008
05:07
Floor
12/02/2008
22:44
ICU
12/14/2008
06:19
Discharge
12/08/2008
10:02
Floor
12/05/2008
05:07
Floor
12/14/2008
06:19
Discharge
12/08/2008
10:02
Floor
12/14/2008
06:19
Discharge
patients per month
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

11. Visualizing event sequences
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

12. From one event sequence...
• Single record [Cousins91], [Harrison94], [Plaisant98], …
Patient ID: 45851737
12/02/2008
14:26
Arrival
12/02/2008
14:26
Emergency
12/02/2008
22:44
ICU
12/05/2008
05:07
Floor
12/08/2008
10:02
Floor
12/14/2008
06:19
Discharge
Time
Patient #45851737 Arrival
Emergency Room
ICU
Floor
Discharge
compact
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

13. To multiple event sequences...
• Search [Fails06], [Wang08], [Vrotsou09], …
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

14. To multiple event sequences...
• Search [Fails06], [Wang08], [Vrotsou09], …
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

15. To multiple event sequences...
• Search [Fails06], [Wang08], [Vrotsou09], …
• Group [Phan07], [Burch08], [Wang09], …
1 {
2 {
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

16. To multiple event sequences...
• Search
• Group
• Summarize?
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

17. Summarize
e.g. 1) What happened to the patients after they arrived?
Arrival
?
?
2) What happened to the patients before & after ICU?
ICU
? ?
? ?
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

18. Overview / Summary
Millions of records
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

19. Challenges
• Display millions of records on one screen
– Limited space (typical monitors)
– Scalability (millions of records?)
– Aggregation
• While preserve important information
– What are all the possible sequences?
– How long is the gap between each pair of events?
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

20. LIFEFLOW
Picture > 1000 words
LifeFlow > 1000 event sequences
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

21. LIFEFLOW
… is novel
… is scalable
… provides the missing overview
… summarizes all possible sequences
and time gap between events
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

22. VIDEO esign
wD
LifeFlo
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

23. DEMO emonstration
wD
LifeFlo
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

24. Case Study#1: Medical
6,000+ Improve the Quality of Care
patients per month
Feedback
• Big picture + anomalies
• Less worry about query formulation,
more time thinking about new questions
• Long-term monitoring
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

25. Case Study#2: Transportation
200,000+ Compare traffic agencies
traffic incidents
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

27. 100 years!

28. Clean the data.
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

29. Video

30. Notification Return to normal
Time
Agency

31. Case Study#2: Transportation
200,000+ Compare traffic agencies
traffic incidents
Feedback
• Reveal unexpected sequences
• Identify data errors
• Can ask more questions, faster, and richer
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

32. User Study
• 10 participants
• Goals:
– Learnability
– Strategies / Problems
• Procedure:
– 12-minute training
– 15 tasks
• Results:
– Participants can perform given tasks.
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

33. Quotes
“Oh! This is very cool!”
“The tool is easy to understand and easy to use.”
“Very easy to find common and uncommon sequences”
“LifeFlow provides a great summary of the big picture.”
“Can I use it with my dataset?”
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

34. Conclusions
• LifeFlow
– Overview
– All sequences + gap between events
• 2 case studies + 1 user study
– Show big picture + reveal anomalies
– New questions from the data
– Easy to learn
• Applicable to many domains
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

35. Acknowledgement
• Washington Hospital Center
Phuong Ho, Mark Smith, David Roseman
http://www.whcenter.org
• National Institutes of Health (NIH)
Grant RC1CA147489-02
http://www.nih.gov
• CATT Lab
Michael Pack, Michael VanDaniker, Nikola Ivanov
http://www.cattlab.umd.edu
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

36. Conclusions
• LifeFlow
– Overview of event sequences
– All sequences + gap between events
• 2 case studies + 1 user study
– See big picture + reveal anomalies
– New questions from the data
– Easy to learn
• Applicable to many domains
HCIL’s 28th Annual Symposium Contact me
May 25-26, 2011 kristw@cs.umd.edu
University of Maryland #HCIL www.cs.umd.edu/hcil/lifeflow
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

37. Q&Aestion?
Any qu
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

38. NK YtOaU welcome.
THA mmen s re
Your co
LifeFlow: Visualizing an Overview of Event Sequences by Krist Wongsuphasawat is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.