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

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.