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Article History

Received: 20 October 2023

Accepted: 2 April 2024

First Online: 11 April 2024

Competing interests

: The authors declare no competing interests.

: We accessed our GPS-based relocation data under a strict agreement with Spectus; the agreement precludes attempts to de-anonymize or disaggregate the data. Spectus reviewed our current study prior to journal submission. While the IPUMS USA data are publicly available, we follow Census Bureau principles by using these data solely for statistical purposes and not attempting to disaggregate or identify any individual within the data samples.

: The Spectus data are collected from de-identified mobile-phone users who have opted in to provide access to their mobility data anonymously through a California Consumer Privacy Act (CCPA) compliant framework. The data provider, Spectus, always asks users to share their location before collecting it. Spectus also requires its application partners to disclose their relationship with Spectus and present users with options to opt out. Prior to sharing data with researchers, Spectus aggregates data to the county level. In order to further preserve privacy, Spectus discards data from counties with low thresholds of user counts.The sampled individuals in the U.S. Census ACS are required by law to respond to the survey, but the Census Bureau is also required by law to protect respondents’ privacy, including ensuring that any identifiable information is removed before publicizing the data.