This report documents a comprehensive comparison of cross sections calculated using different methodologies and codes, including CASMO, HELIOS, and TRITON XS. The conclusions from this study have resulted in this guidance document on how to choose cross section histories and branches for boiling water reactor (BWR) analysis, and the methodology to collapse the fine-energy and -space fluxes calculated by the detailed lattice calculation. The guidance herein is applicable to all BWR designs.