Table 1. Selected challenges and solutions since the inception of All of Us.

Challenges	Solutions
Recruitment of 1 million participants by the end of 2026	Increased recruitment sites nationwide (5); orderly shutdown and enrollment restart during the COVID-19 pandemic; virtual/app and web-based enrollment, with saliva samples sent by mail instead of blood collected in person; diverse enrollment partnerships; enrollment “surge strategy” in 2022 (8)
Diversity of participants	>50 engagement partners; a diversity of enrollment sites; mobile enrollment vehicles; enrollment from Federally Qualified Health Centers; participant ambassadors (3,5)
Broad data collection protocol	Commitment and consent (9) to capture five data streams
Data access and privacy	Workbench workshops and tools; tiered access requiring adherence to privacy rules
Data harmonization	Use of OMOP as a standard for most phenomic data, and GA4GH standards for genomic data (10)
Regulatory	Central Institutional Review Board; early partnership with FDA on return of genetic results and investigational device exemption approval (11)

OMOP, Observational Medical Outcomes Partnership; GA4GH, Global Alliance for Genomics and Health