Average, rather than point specific temperature measurement is important in a number of industrial situations. In this work, a method to improve this type of measurement using the fluorescence lifetime-related mathematical parameter, the singular value (SV), is discussed in detail. The analysis reported shows that with rare-earth doped fibers used as temperature sensor probe elements, for average temperature measurement, such a system works well especially when the lifetimes obtained from different sensing probes are very close to each other. The SV scheme, based on matrix theory, is important because the average temperature-dependent singular value possesses the characteristics of both high speed and high precision. Using the method, an average temperature sensing scheme is demonstrated in experiments carried out over the region from 20 to 100 °C, in whichNd3+doped fibers are employed as the intrinsic temperature sensor elements. When two temperature sensing probes are used in the measuring region, the precision determined for the average temperature estimation is±3.6 °C.When three sensors are employed instead of two, the precision is similar at±3.4 °C.Results obtained indicate that with more sensor elements used in the sensing region, the accuracy achieved is not diminished due to the averaging effect in the measurement. ©1998 American Institute of Physics.