In 1995, Andrew H. Criddle made a statistical study of Clement's letter to Theodore with the help of Otto Stählin's concordance of the writings of Clement. According to Criddle, the letter had too many hapax legomena, words used only once before by Clement, in comparison to words never before used by Clement, and Criddle argued that this indicates that a forger had "brought together more rare words and phrases" found in the authentic writings of Clement than Clement would have used. The study has been criticized for, among other things, focusing on "Clement's least favourite words" and for the methodology itself, which turns out to be "unreliable in determining authorship". When tested on Shakespeare's writings only three out of seven poems were correctly identified.