The Global Positioning System (GPS) is an extremely effective satellite-based system that broadcasts sufficient information for a user to determine time and position from any location on or near the Earth. The fundamental GPS measurement is the corrected time of the satellite clock relative to the receiver clock. This paper uses publicly available information to present a statistical analysis of the underlying timescale and clock performance, which can be largely presented without recourse to the many significant and interesting scientific corrections and parameterized models that could or must be applied to the data.