 This paper examined the accuracy of Landsat 8 OLI's reflectance-based calibration results against ground-based measurements. The results showed that OLI was accurate to within plus or minus 3% in most cases, with the exception of OLI band 7, which was accurate to within plus or minus 5%. Additionally, the results from the tandem Landsat 7 and 8 flights indicated that ETM Plus and OLI agreed to within plus or minus 2% and similar bands in top-of-atmosphere spectral radiance and to within plus or minus 4% in top-of-atmosphere spectral reflectance. This article was authored by Jeffrey Zapplemeyers, Joel McCorkle, Nikolaus Andersen, and others.