1. A method for ascertaining error types for incorrect reading results from an OCR reader for text units which have a standard content structure and are subdivided into distinguishable sections, using true reference data, characterized in that the reference data for the respective incorrectly read text unit are used for automatically ascertaining the respective text unit with the associated sections in a dictionary for the text units which contains a text unit, subdivided into individual, distinct sections, for each searchable entry, in that the reading result data are used to search the dictionary for a text unit with associated sections, the sections found with the respective corresponding reference sections are compared pair by pair, and in that the respective incorrect reading result is classified into stipulated error classes on the basis of the discrepancies ascertained in the pair by pair comparison.