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
Synthetic measure Synthetic measure A synthetic measure (or synthetic indicator) is a value that is the result of combining other metrics, which are measurements of various features. There is a method to measure quality of service in hotels. In related study authors aggregate tourist opinions, measured on a scale from 1 to 10. Synthetic measure (indicator) of service quality in each hotel is calculated with the help of the aggregation operator. Other study proposed to use classical parameters EV, PV and AC to carry out the synthetic measure of project performance. Different normalized stimulants and destimulants were used in research to create