Why shear measurement is hard, and what to do about it
Weak lensing measurements are a cornerstone of the coming wave of ground and space-based dark energy probes. All lensing measurements to date have been challenged with calibration problems that typically comprise one of the dominant sources of systematic bias. In this talk, I will show why this problem has deep roots and explain what I think are the limitations of existing methods. I will then describe our proposed general solution, called Metacalibration, which has been implemented for the Dark Energy Survey data.