Any accurate research about analytic techniques applicable to music of the 20th century will easily reveal how much aleatoric music represents a desolate territory for this kind of approach. It is well known, after all, that aleatoric music is an extremely peculiar subject. Its atypical nature (a unique musical praxis expression of a unique aesthetic programme) is indeed what makes standard analytic approaches nearly useless. This is a shortcoming which shows up clearly anytime we attempt to go through that inventory of unconventional scores and/or bizarre composition techniques in order to discern common patterns and outline an index of basic aleatoric music forms. Exploring the analytical possibility in aleatoric music therefore presupposes the setting of specific analytical tools. But so far, despite a recent contribution, this type of device seems not available yet.
Moving foward from the taxonomy presented by Decroupet in 1997, the intent of this paper is to introduce a new comprehensive analytical tool applicable to aleatoric music. The principle underlying this tool is a rigorous definition of the seven structural basic elements which make a piece of music  aleatoric. Its purpose, in essence, is to provide musicologists with a step by step empirical analysing procedure suitable to identify those elements, with regard to music scores and music composition techniques. Furthermore, the tool provides users with a referential classification table (see taxonomy). Once the analysis is completed, this reference table shows how to classify the score and/or the composition techniques into one of the major aleatoric music forms: chance music and indeterminate music – this last one with its own 63 different forms. Supported by a detailed explicative paper this tool has a compact graphic grid layout (it fits a book page), and is suitable for preparing  comparative analysis, with reference to a set of aleatoric music pieces chosen by the user.