OP,
I wouldn't say TF by itself is a ranking factor, because as so many have stated, G wouldn't use a third party metric as a ranking factor. However, Google has its own way to calculate trust and it does play a role in ranking websites.
I came up with an acronoym to help myself remember, it's A.R.T.
Authority + Relevancy + Trust = Rankings
(I didn't come up with the formula but "I made it look good" by switching it into a acronym)
Not saying you can't fool G into thinking you have all 3. All you need is a PBN, SAPE & SPAM (Tier-2), Social Signals and a few Guest Posts/Editorial Links