From the wiki page on "Seduction of The Innocent":
Wertham "manipulated, overstated, compromised, and fabricated evidence" in support of the contentions expressed in Seduction of the Innocent. He intentionally mis-projected both the sample size and substance of his research, making it out to be more objective and less anecdotal than it truly was. He generally did not adhere to standards worthy of scientific research, instead using questionable evidence as rhetorical ammunition for his argument that comics were a cultural failure.
Link to the book:
The Black Terror 02