I admit, I have not and probably will not read the article, but the title made me think of this:
In school, a child's reading level is often measured by his/her
Lexile. A student's Lexile number is determined by a test that measures the reader's comprehension level through having them read a passage and then answer questions without consulting the text.
The average adult novel is in the
800 to 900 lexile range (approximately on par for middle school level).
The Series of Unfortunate Events books range from
1010 to 1370, Harry Potter and the Half-Blood Prince is
1030 and
Tales of Beedle the Bard is
1290.