As all experimental procedures, Experimental Modal Analysis (EMA) is subject to a wide range of potential testing and processing errors. The modal identifications methods are sensitive to these errors, yielding modal results which are uncertain up to certain error bounds. The question is hence what these errors bounds on test data and modal parameters are, how these can be reduced but also how these errors will affect the actual use of the data. The paper reviews the main elements of the test data and modal modelling uncertainty and assesses the impact of the uncertainty on some tipical modelling problems. Some recent methods for uncertainty analysis in modelling are adressed.
