Not all drafts are the same, but the results are pretty consistent. Maybe if we pick a corner in every round we'll exceed the norm, but it isn't likely we'll do that. The corner we do pick, if we even pick one or two, could also turn out to be a failure. It happens, and it happens with a great deal of regularity.
Most years some position is considered to be strong, but our success rate (and that of other teams as well) remains consistent. Let's say because of the strength of the position and how the draft falls we don't end up taking a cornerback until the fourth round. The probability of that player becoming a starter is not that high. Yes, some players taken in the fourth round will become starters but the percentages are against your team being one of the lucky ones. Maybe because of the depth of these corner group we'll stand a better chance, but it's still not a high percentage.
This is from
http://www.arrowheadpride.com/2015/2/20/8072877/what-the-statistics-tell-us-about-the-draft-by-round from 2015 but there are other good statistical sites on the draft as well:
Finally, we come to the largest drafted group in the last decade. Nearly, 21% of all players drafted in the last decade are defensive backs.
- Of the 510 defensive backs drafted, 121 became starters.
- You have the same success rate drafting a DB in the 7th round as you do drafting one in the 4th (11%)
- On average, you have the following number of DBs taken per round: 1st - 6, 2nd - 6, 3rd - 7, 4th - 8, 5th - 8, 6th - 7, 7th - 9
- After you get past the success rates of the first two rounds (64% in the first, 46% in the second), there isn't a huge difference in success (24% - 3rd, 11% - 4th, 17% - 5th, 8% - 6th, 11% - 7th)
- DBs provide the best success potential in the 7th round versus other positions in that round.
Historic Success Chart
The numbers show us the following outline for finding consistent starters:
1st Round - OL (83%) LB (70%) TE (67%) DB (64%) QB (63%) WR (58%) RB (58%) DL (58%)
2nd Round - OL (70%) LB (55%) TE (50%) WR (49%) DB (46%) QB (27%) DL (26%) RB (25%)
3rd Round - OL (40%) TE (39%) LB (34%) DL (27%) WR (25%) DB (24%) QB (17%) RB (16%)
4th Round - DL (37%) TE (33%) OL (29%) LB (16%) WR(12%) DB (11%) RB (11%) QB (8%)
5th Round - TE (32%) DB (17%) WR (16%) OL (16%) DL (13%) RB (9%) LB (4%) QB (0%)
6th Round - TE (26%) OL (16%) DL (13%) WR (9%) DB (8%) RB (6%) LB (5%) QB (0%)
7th Round - DB (11%) OL (9%) QB (6%) WR (5%) DL (3%) LB (2%) RB (0%) TE (0%)