Procrustes Analysis is a Morphometric method based on Configurations of Landmarks that estimates the superimposition parameters by least-squares; for this reason, the procedure is very sensitive to outliers. There are classical results, based on the normality of the observations, to test whether there are significant differences between individuals. In this paper we determine a Von Mises plus Saddlepoint approximation for the tail probability (p-value) of this test for the Procrustes Statistic, when the observations come from a model close to the normal.
García-Pérez, A. (2018). Robust Morphometric Analysis Based on Landmarks. In: Gil, E., Gil, E., Gil, J., Gil, M. (eds) The Mathematics of the Uncertain. Studies in Systems, Decision and Control, vol 142. Springer, Cham. https://doi.org/10.1007/978-3-319-73848-2_16
