The Technical Spectrum Efficiency Factor (TSEF) concept was developed in the Technical Subcommittee (TSC) of the Interdepartment Radio Advisory Committee (IRAC) and was applied, by NTIA, to government fixed telecommunications systems in the 7-8 GHz bands. Both computer automated and manual procedures were employed. The TSEF evaluates the technical spectrum efficiency of a spectrum-using system by comparing the amount of the spectrum it uses to that used by the most spectrum-efficient system that could be procured to accomplish the same mission. The "most spectrum-efficient" system is called "the reference system". An extensive catalog of spectrum conservation techniques is also included.