Back to the App:The Costs of Mobile Application InterruptionsLuis A. Leiva1, Matthias Böhmer2, Sven Gehring2, Antonio Krüger21 Universitat Politècnica de València // Institut Tecnològic dInformàtica2 DFKI // Ubiquitous Media Technology Lab
Mobile phones evolved from communication devices...
What are the costs of app interruptions? - When switching between applications? - When being interrupted by a phone call?
In this note...‣ We present a framework for detecting interruptions from mobile app usage logs‣ We investigate the costs and frequency of app interruptions - Intentional app-switching behavior - Interruptions by incoming phone calls‣ We discuss strategies for mitigating interruptions
Study Dataset 3.6K unique users 15.7K different apps 1.5 years 5.5M data samples
Detecting Interruptions ... app use ... time‣ App use contained in log ﬁle - Timestamp of start of use - Duration of use‣ We keep track of usage time of apps
Detecting Interruptions ... app use interruption app use cont‘d ... time‣ Mining for interruptions - Internal interruptions: another application - External interruptions: incoming phone call‣ We know the duration of the interruption
Measuring Interruptions Runtime of non-interrupted app app use time Duration of interrupted app use app use app use cont‘d time Duration of interruption interruption time app use overhead Duration of overhead app use app use cont‘d time
Study Results‣ Internal interruptions are more frequent and involve more apps external internal Interruption data samples 776,922 970,543 Interrupted users 1,929 [1,676] 2,926 [2,609] Interrupted Applications 1,373  4,626 [1,043] [paired samples denoted in brackets]‣ Our analysis is based on paired cases
Occurrences of App Interruptions external internal Daily interruptions (% usage) 3.2 (2.2) 8.3 (5.3) per user Interrupted applications 3.3 (2.6) 8.7 (7.2) mean (SD)‣ Interruptions do not happen as often as expected - 3% of app use is interrupted by phone calls (external) - 8% of app use is interrupted by app switching (internal)
Impact of App Interruptions external internal Regular app runtime (s) 24.8 (31.8) 18.9 (24.4) Runtime when interrupted (s) 107.1 (121.1) 87.9 (75.5) per app Interruption duration (s) 12.5 (8.1) 23.7 (19.3) Overhead duration (s) 43.2 (65.9) 34.4 (40.7) mean (SD)‣ If interruptions happen, resumption costs may be exceedingly high
Design Implications‣ Help to regain context of deferred application when resumed, inspired by previous approaches in ﬁeld of desktop interruptions‣ Preventive: Prepare user for being interrupted - Postponing phone call for a few milliseconds - Gradually overlaying phone call instead of full-screen popup‣ Curative: Guide user back into task - Replaying last milliseconds of UI interactions - Leave visual cues on screen to hint where to continue - Vanish interruptive application into point of last focus
Conclusion‣ Main Findings: - Application interruptions are happening rarely - If interruptions happen, they are costly - App-switching behavior is not as often as assumed - Call interruptions add signiﬁcant overhead to app use‣ Future Work: - Enriching data collection process with experience sampling methods to get more insights into context of interruptions - Model for predicting interruption overhead to inform the means of curation‣ Thank you :-)