R-value (insulation) contain no trapped CFCs or HFCs (e.g., half-pound low density foams). On certain brands, twenty-year tests have shown no shrinkage or reduction in insulating value. This has led to controversy as how to rate the insulation of these products. Many manufacturers will rate the R-value at the time of manufacture; critics argue that a more fair assessment would be its settled value. The foam industry adopted the LTTR (Long-Term Thermal Resistance) method, which rates the R-value based on a 15-year weighted average. However, the LTTR effectively provides only an eight-year aged R-value, short in the scale of a building that
Quality of results accepted as a good quality of result – relative density of combinational logic component – while a relative density of fifty will indicate severe design problems (routability, technology that is being used, etc.) which should be investigated and addressed. "Note:" A new term "Quality of Silicon" (QoS) is being promoted by the EDA industry in an attempt to measure the performance of backend EDA tools, like Xilinx ISE from Xilinx, or tools from Synopsys or Cadence Design Systems in isolation from the human designer's own performance in the frontend design stage. It is claimed that for historical reasons QoR is,