"In economics, diminishing returns (also called diminishing marginal returns) refers to how the marginal production of a factor of production starts to progressively decrease as the factor is increased, in contrast to the increase that would otherwise be normally expected. According to this relationship, in a production system with fixed and variable inputs (say factory size and labor), there will be a point beyond which each additional unit of the variable input (i.e., man-hours) yields smaller and smaller increases in outputs, also reducing each worker's mean productivity. Conversely, producing one more unit of output will cost increasingly more (owing to the major amount of variable inputs being used, to little effect)."
A lot of talk about the Miami draft centers around whether to improve an already good offense to great instead of focusing on making a bad defense good.
This is usually applied to Spiller or Bryant, but the specific players involved aren't that relevant here.
Also not relevant here is whether this is an offense or defense oriented league. (It is still a zero-sum game, no matter how the logic is justified. You win by scoring more, yes. Conversely, you lose by allowing the other team to score more. Both are equally valid.)
But what is relevant here is that every post I have read on the subject ignores a simple concept. It is related to the concept of diminishing returns. In baseball they use the term marginal wins, etc. Also marginal utility is more directly appropriate, but diminishing returns is more familiar.
Whatever you call it, the concept for our purposes is simple:
If you are going to draft a great player, you get greater value if that great player is replacing a poor player instead of replacing an average or good player.
It's that simple.
Taking one position from a 7, let's say, to a 10 will not be nearly as valuable as taking another position from a 3, say, to a 10. See?
Even if Spiller or Bryant were going to be perfect 10's, it still isn't the same team improvement as taking a 3 to an 8 or whatever.
That's what all these "Let's take our offense elite!" posts don't understand. You want to improve your team as much as possible. That means making sure you don't have 3's and 4's running around creating massive weaknesses for other teams to exploit.
(Additionally, I would argue that while offenses can play to their strengths, thus masking weaknesses to some extent, defenses have to react to the offense, so they don't get to choose whether or not the play will be directed at a weakness. At least not to the extent that offenses can.)
Bottom line is that if you have weaknesses on your team, you will generally get a lot more value for you buck/pick by replacing those with elite players than you will from replacing good players with elite players.
Now, there are all kinds of adjustments and small exceptions to this, based on value of position, etc. But we're not talking about quarterbacks vs. long snappers here. And the concept remains the same. If your focus is on getting good value from the draft, spending high picks on offensive players for us right now is past the point of diminishing returns. Unless you believe our offense sucks, but facts are against you on that anyway.
So think about the concept of diminishing returns as you ponder who you want to draft. Getting the most out of each pick is not just about how good that player is, it is also about how good or bad the player he would be replacing is. Those together determine value.