A two‐level directional model for dependence in circular data

Abstract We present a likelihood‐based test for clustering among sub‐population mean directions for circular data. The test is based on a two‐level hierarchical model with von Mises distributed variation on each level. The properties of the tests are investigated and compared to the commonly applied techniques of second‐order analysis and pseudo‐pooling of directions for the situation at hand. Finally we apply the technique to some previously published data sets, to determine the presence of directional clustering among the sub‐populations. The Canadian Journal of Statistics 45: 461–478; 2017 © 2017 Statistical Society of Canada