Focus on this artwork and analyze the Attribution.
In the late 1980s antiquity scholars, and Getty Museum curator, Frel, used radiocarbon dating and stylistic analysis to attribute Lysippos as the creator of the Youth.  Using Polykleitos's statues as a comparison, scholars seen a change in Polykleitan Kanon; the proportions become more subtle and richer in detail.  There was a shift from the squareness in the face and innovative applications of elongation in the details of face and body.  Lysippos was praised for his ability to evoke the soul from his statues through fleeting expressions.  Establishing an exact artist for the work is challenging due to the lack of original Greek bronzes to use for comparison. Ancient literature gives testimony of the classical sculptors; however, the artist did not sign the statues. There is no physical evidence to support the conclusion that Lysippos was the sculptor, but Frel, Mattusch, and ancient literary source Pliny, theorizes that Lysippos or his student was the Youth's creator. In Pliny's Natural History, he includes information about Greek sculptors extracted from earlier texts that are lost to us.  During the fourth century B.C., Lysippos produced a multitude of sculptures; he alone probably sculpted fifteen hundred statues.  He came from a family of bronze workers who developed a new method of increasing production, and the statues of athletes were a specialty.
Getty Museum Polykleitos Lysippos Pliny