Indicators of retention in remote digital health studies: A cross-study evaluation of 100,000 participants. Pratap A, Neto EC, Snyder P, Stepnowsky C, Elhadad N, Grant D, Mohebbi MH, Mooney S, Suver C, Wilbanks J, Mangravite L, Heagerty P, Arean P, Omberg L. arXiv preprint arXiv:1910.01165. 2019 Oct 2