Comparing Privacy Labels of Applications in Android and iOS

The increasing concern for privacy protection in mobile apps has prompted the development of tools such as privacy labels to assist users in understanding the privacy practices of applications. Both Google and Apple have mandated developers to use privacy labels to increase transparency in data collection and sharing practices. These privacy labels provide detailed information about apps' data practices, including the types of data collected and the purposes associated with each data type. This offers a unique opportunity to understand apps' data practices at scale. In this study, we conduct a large-scale measurement study of privacy labels using apps from the Android Play Store (n=2.4M) and the Apple App Store (n=1.38M). We establish a common mapping between iOS and Android labels, enabling a direct comparison of disclosed practices and data types between the two platforms. By studying over 100K apps, we identify discrepancies and inconsistencies in self-reported privacy practices across platforms. Our findings reveal that at least 60% of all apps have different practices on the two platforms. Additionally, we explore factors contributing to these discrepancies and provide valuable insights for developers, users, and policymakers. Our analysis suggests that while privacy labels have the potential to provide useful information concisely, in their current state, it is not clear whether the information provided is accurate. Without robust consistency checks by the distribution platforms, privacy labels may not be as effective and can even create a false sense of security for users. Our study highlights the need for further research and improved mechanisms to ensure the accuracy and consistency of privacy labels.