At first there seemed to be little consistency of results in trials varying the factors presumed to be relevant. A new cladogram resulted from any change, which suggested that the method was not capturing the underlying evolution of languages but only reflecting the extemporaneous judgements of the researchers. In order to find the factors that did bear on phylogeny the researchers needed to have some measure of the accuracy of their results; i.e., the results needed to be calibrated against known phylogenies. They ran the experiment using different assumptions looking for the ones that would produce the closest matches to the most secure Indo-European phylogenies. Those assumptions could be used on problem areas of the Indo-European phylogeny with greater confidence.