Adjusted Peak Performance (APP) is a metric introduced by the U.S. Department of Commerce's Bureau of Industry and Security (BIS) to more accurately predict the suitability of a computing system to complex computational problems, specifically those used in simulating nuclear weapons.
Further details can be found in the document "Practitioner's Guide To Adjusted Peak Performance".
APP was itself replaced in November 2007 when the BIS amended 15 CFR to include the December 2006 Wassenaar Arrangement Plenary Agreement Implementation's new metric - Gigaflops (GFLOPS), one billion floating point operations per second, or TeraFLOPS, one trillion floating point operations per second.
The unit of measurement is Weighted TeraFLOPS (WT) to specify Adjusted Peak Performance (APP).
For example, a PowerPC 750 running at 800 MHz would be rated at 0.00024 WT due to being able to execute one floating point instruction per cycle and not having a vector unit.