Trades of draft picks are negotiated against a numerical scale that assigns a value to every selection. The scale is known to be inaccurate and is still used constantly.
The chart solves a coordination problem
Two teams trading picks must agree on what those picks are worth, and without a shared reference every negotiation starts from nothing.
A published scale gives both sides a common starting point, so discussion moves quickly to what each team wants rather than to abstract valuation.
Speed matters because draft-day trades are often agreed within the minutes allocated to a selection.
The curve is steeper than the evidence supports
The traditional chart drops sharply at the top, so the first pick is worth several times the tenth and the difference narrows quickly afterwards.
Studies of actual player production suggest a much flatter curve, because early selections fail often enough that their expected output does not justify the premium.
The gap between the two is why trading down has been a persistent source of advantage for teams willing to act on it.
Cost is part of the value
Rookie contracts are set by draft position, so a high pick carries a large guaranteed salary while a later pick carries a small one.
A late-first-round player who performs adequately therefore delivers better value per dollar than a top pick who performs well, because the surplus over his contract is larger.
Any valuation that ignores contract cost overstates the top of the draft, which is exactly what the traditional chart does.
Why teams still use it
A team that privately values picks differently can still trade against the public chart and capture the difference.
Abandoning the shared scale would remove that opportunity, since it depends on the counterparty using the conventional numbers.
Most teams therefore maintain an internal valuation and negotiate publicly against the common one, which keeps the chart alive despite widespread agreement that it is wrong.
Future picks carry a discount
A pick in next year's draft is worth less than the equivalent this year, because its eventual position is unknown and the value arrives later.
Conventional practice discounts a future selection by roughly a round, which is a rough adjustment rather than a calculated one.
Teams under pressure to win immediately accept that discount readily, which is why rebuilding teams accumulate future picks from contenders each season.