One of the most exciting areas of research in cosmology is the effort to extract information about fundamental physics from observations of the universe on large scales.  With the advent of increasingly large cosmological datasets (and correspondingly small statistical uncertainties), future progress in the field will fundamentally be determined by our ability to understand and account for systematic errors. In this talk, I’ll discuss two projects which further that ability: a study of how reliably we can separate primordial and late-time contributions to large-angle features of the the Cosmic Microwave Background (CMB) and the development of a blinding strategy to prevent experimenters’ bias from influencing the Dark Energy Survey’s cosmological analysis.