Relation between word types and vocabulary density.

[nablator]

You simply divide the total word count (tokens) by the number of different words (types).

Or the other way around: TTR is types/tokens.

Did you check the published orders of Q13 vs the MATTR order too ?

If MATTR does have a general tendency to decrease (at least in Currier B) when the bifolios are correctly (?) reordered, Q13 looks like it was written last and is an evolutionary dead end: it devolved to the point of being a parody. Either it was really written last or they noticed that it was bad and did something to bring the MATTR back to normal later, in Q20.