Replacing discontinued Big Tech mobility reports: a penetration-based analysis

TL;DR

This paper analyzes a large smartphone trajectory dataset to determine the minimum data set size needed to reliably replace discontinued Big Tech mobility reports, ensuring continued mobility trend monitoring.

Contribution

It establishes a lower bound on data set penetration required for effective replacement of Big Tech mobility reports using independent smartphone trajectory data.

Findings

A lower bound of 10^-4 to 10^-3 in data penetration guarantees high adherence.

Small data sets, representing 1 in 1,000 to 10,000 individuals, are sufficient for reliable mobility analysis.

The study provides a quantitative basis for developing alternative mobility data sources.

Abstract

People mobility data sets played a role during the COVID-19 pandemic in assessing the impact of lockdown measures and correlating mobility with pandemic trends. Two global data sets were Apple's Mobility Trends Reports and Google's Community Mobility Reports. The former is no longer available, while the latter will be discontinued in October 2022. Thus, new products will be required. To establish a lower bound on data set penetration guaranteeing high adherence between new products and the Big Tech products, an independent mobility data set based on 3.8 million smartphone trajectories is analysed to compare its information content with that of the Google data set. This lower bound is determined to be between 10^-4 and 10^-3 (1 trajectory every 10,000 and 1000 people, respectively) suggesting that relatively small data sets are suitable for replacing Big Tech reports.