It seems that a lot of people are using the word “stick-to-it-iveness”. There’s even a page for potential authors that lists “stick-to-it-iveness” as a critical trait.
As this excellent rant points out, people seem to ignore that we already have a word for that: tenacity.
Even sadder: Google reports 995 hits for sticktoitiveness, 2810 for stick-to-it-iveness, and more with various other spellings. Argh.