California Building Energy Code Compliance tool for commercial buildings (CBECC-Com) was developed by the California Energy Commission. CBECC-Com is used to demonstrate compliance with the California Energy Code, Title-24, through the Nonresidential Alternative Compliance Method (NACM). A preliminary step in developing CBECC-Com was the creation of a ruleset that provides a standardized approach for performing energy modeling as required by the NACM in Title 24. A similar ruleset for analyzing performance compared to ASHRAE 90.1-2010 using the Appendix G Performance Rating Method (PRM) has been developed by the Pacific Northwest National Laboratory (PNNL) through funding support from the Department of Energy (DOE). The Performance Rating Method Reference Manual (PRM-RM) and tools like CBECC-Com are intended to significantly reduce effort to generate a baseline model, remove the ambiguity involved in the interpretation of performance based ruleset requirements and provide a standardized approach for the development of a baseline model. This paper discusses the technical approach used for the development of the PRM-RM following the model used in CBECC-Com.