E.g.: One of the words I encountered in the test was 'terpsichorean'. While I knew that Terpsichore is one of the Muses, I did not know which one and left the box unticked. Had there been multiple choices, I might have guessed the correct solution.
Google tells me it means dancing so I was way way off (maybe conflating turquoise and cerulean?).
But I have no way of knowing how many words that I feel comfortable defining are actually nowhere near correct, so to be any kind of accurate, they need to do some verification of correctness. All 'honesty' means is 'don't deliberately cheat' not 'don't be dumb'.
However, I think a multiple choice test could also inflate scores unless the definitions were very cunningly constructed.
I scored 75-80th percentile (32,800) which surprised me. It seems quite a lot of words, for one. For another I consider my vocab' to be very good and I don't think I'm being bigheaded in that. Ergo I expected to be ranked higher.
On the second page there was an entire column of words of which I recognised only three sufficiently to provide a guaranteed accurate definition. One of that column was terpischorean, another tatterdemalion.
Whilst looking up tatterdemalion I found little use of it after the 1930s except as a proper noun (a Marvel Comics character for example). What I did find however is that Google Books is useless for finding dates. One citation from an author Sir Edward Bulwer Lytton is given a date of 1999. That's a reprint date, the author died in the 19th century.
BTW, the word is 'deduce' ;)
To my defense, they are both derived from 'deducere', to lead away, and 'were not distinguished in sense until the mid 17th cent' according to my system’s dictionary