The article I posted has it by pick so you don't get arbitrary distinctions.
Not sure how many comp picks get added in a given year (without looking closer) but I went with pick #104 for the equivalent of 4.02, which is where I thought I remembered Carter going. The odds there for an RB2 season are ~16.x%, which is basically 6 to 1.
If I draft two of these types of RBs each year, I will hit once every 3 years. But contrary to my first post above, the (very) early returns are showing Pierce and Spiller as mid to late 2nd round picks. I have seen people post rookie drafts where one or the other had fell to the 3rd (that might be silly).
Well, from a franchise capital POV, a late 2nd or early 3rd is worth something in the neighborhood of 5/300 Franchise Points*, whereas the "reach into the 1st for Sermon/Carter" is more like 20/300 Franchise Points. The first is spending 1/60th of my assets on a 1/6 dart throw. Versus the second where it is 1/15. To throw 6 darts I would be spending 40% of my franchise value. Good way to go insolvent.
But in the first scenario, it is a slam dunk. 1/60 and 6 dart throws takes 1/10 or 10%. If you are only taking 2 per year you are only giving up 3.3% of franchise value each year spread out over time. You *should* have plenty of other assets that outgrow that small price during that time.
Or just acquire picks and take all 6 dart throws in one draft. Pierre Strong. Zamir White. Dameon Pierce. Isaiah Spiller. Tyrion Davis-Price. Brian Robinson. 10% or 30 Franchise Points all on the table at once.
When one of them hits you break even. But this isn't an exact science as much as we try. 3rds and late 2nds that don't pan out really don't mean squat. But when they hit it is profitable.
Everything is about pot odds. We should be trying to take as many dart throws as we can possibly and reasonably afford. Do WRs at 4.02 hit at a rate that represents a value gained advantage to one's roster? Really? If you told me they hit there at 19% over the 16% for RBs, should I care? Is that enough to say "don't *ever* draft a RB taken there regardless of what scrub WR might be on the board?" Or QB or TE or vet or whatever.
Anyway TLDR people point at 16% and say that is a bad bet. Well not if you can afford to keep spinning the wheel.
*part of our FFPC thread conversations about the Hindery charts and quantifying an entire team in such a fashion. I have written a lot about it.
R - you’ll be more likely to get value out of a PPR receiving back over time than one of the depth backs a team drafted late. 
