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ESE Fall Seminar – “Large Observational Study of the Causal Effects of a Nudge and the Geometry of Causality”
September 26, 2023 at 11:00 AM - 12:00 PM
Nudges are interventions promoting healthy behavior without forbidding options or significant incentives. As an example of a nudge, the Apple Watch encourages users to stand by delivering a notification if they have been sitting for the first 50 minutes of an hour.
Based on 76 billion minutes of observational standing data from 160,000 subjects in the public Apple Heart and Movement Study, amount of data in the field that makes this work one of the largest ever in the subject, we estimate the causal effect of this notification using a novel regression discontinuity design for time-series data with time-varying treatment. We show that the nudge increases the probability of standing by up to 44%, a very significant effect compared to what has been reported in the literature, remaining effective with time, even after almost 2 years. The nudge’s effectiveness increases with age, and it is independent of gender. Closing Apple Watch Activity Rings, a visualization of participants’ daily progress in Move, Exercise, and Stand, further increases the nudge’s impact. We conclude the presentation with some recent work on connections between geometry and causal inference.
The first part of the presentation is joint work with Achille Nazaret while the second is with Amir Farzam and Allen Tannenbaum.
Guillermo Sapiro
James B. Duke Distinguished Professor of Electrical and Computer Engineering, Duke
Guillermo Sapiro was born in Montevideo, Uruguay, on April 3, 1966. He received his B.Sc. (summa cum laude), M.Sc., and Ph.D. from the Department of Electrical Engineering at the Technion, Israel Institute of Technology, in 1989, 1991, and 1993 respectively. After post-doctoral research at MIT, Dr. Sapiro became Member of Technical Staff at the research facilities of HP Labs in Palo Alto, California. He was with the Department of Electrical and Computer Engineering at the University of Minnesota, where he held the position of Distinguished McKnight University Professor and Vincentine Hermes-Luh Chair in Electrical and Computer Engineering. Currently he is a James B. Duke School Professor with Duke University. He is also with Apple, Inc., where he leads a team on Health AI.
G. Sapiro works on theory and applications in computer vision, computer graphics, medical imaging, image analysis, and machine learning. He has authored and co-authored over 500 papers in these areas and has written a book published by Cambridge University Press, January 2001.
G. Sapiro was awarded the Gutwirth Scholarship for Special Excellence in Graduate Studies in 1991, the Ollendorff Fellowship for Excellence in Vision and Image Understanding Work in 1992, the Rothschild Fellowship for Post-Doctoral Studies in 1993, the Office of Naval Research Young Investigator Award in 1998, the Presidential Early Career Awards for Scientist and Engineers (PECASE) in 1998, the National Science Foundation Career Award in 1999, and the National Security Science and Engineering Faculty Fellowship in 2010. He received the Test-of-Time award at ICCV 2011 and at ICML 2019, only researcher to receive Test-of-Time awards in both computer vision and machine learning major venues. He was elected to the American academy of Arts and Sciences in 2018 and to the National Academy of Engineering in 2022. G. Sapiro is a Fellow of IEEE, SIAM and was the founding Editor-in-Chief of the SIAM Journal on Imaging Sciences.