Methods for the automatic creation of a category tree with respect to the contents of a data stock, wherein a taxonomy of the data stock will be created on the base of co-occurrences. Another object of the present invention is furthermore a data processing system comprising data which represent information in at least one data stock which is accessible via at least one data source, which is designed and/or adapted to at least partially carry out a method according to the invention. Another object of the present invention is furthermore a data processing device for the electronic processing of data, comprising a control and/or computer unit, an input unit and an output unit, which is designed and/or adapted to at least partially carry out a method according to the invention, preferably using at least a part of a data processing system according to the invention.