  A detailed examination of issues associated with proton radius extractions
from elastic electron-proton scattering experiments is presented. Sources of
systematic uncertainty and model dependence in the extractions are discussed,
with an emphasis on how these may impact the proton charge and magnetic radii.
A comparison of recent Mainz data to previous world data is presented,
highlighting the difference in treatment of systematic uncertainties as well as
tension between different data sets. We find several issues that suggest that
larger uncertainties than previously quoted may be appropriate, but do not find
any corrections which would resolve the proton radius puzzle.
