Structural identification alludes to the fact that it should be possible to determine the dynamic characteristics of a structure from either field measurements or from experimentally obtained data. The importance of this activity cannot be overstated, as structural ageing requires comparing this current structural data with existing benchmarks so as to decide if repairs and/or strengthening measures are required. As previously discussed, the dynamic characteristics of a structure can be determined using modal analysis. In order to get accurate results however, it is important to choose the parameters to be quantified carefully and to measure them accurately. It is also important that structural identification techniques are cost-effective and easy to use.