EARTH CITY, Mo. -- There's probably no better indicator of success in the NFL draft than simply going with wins and losses.

But as metrics have advanced, other methods for evaluating such things have evolved as well. One such method is the use of "Approximate Value." It's a relatively new statistic that has been developed as a means to replicate what "wins above replacement" has become to baseball.

Approximate value assigns a single number intended to indicate performance in a single season for every player. The formula to reach that number is explained here. The goal is to use that number to compare players across positions and seasons.

To evaluate draft performance, those numbers are used across a player's first four seasons (which is now the standard length of a drafted rookie contract) and compared to the expected value of a player taken in his particular draft spot. In most cases, first-round picks are expected to perform the best, so the teams that draft the best are the ones who generally make hay in the later rounds.

With all of that context out of the way, it should come as no surprise to see the St. Louis Rams rank as one of the five worst drafting teams in the league since 2002. Fans of the team don't need the numbers to tell them that players such as Jimmy Kennedy, Tye Hill, Alex Barron, Adam Carriker and so many others qualify as draft whiffs. The number of losses on the team's ledger in that time states that clearly.

According to ESPN Stats & Information, the Rams are joined by Detroit, Oakland, Tampa Bay and Cleveland as the five worst drafting teams in that span. Again, not a surprise given the results on the field. Using those metrics, Stats & Info ranks the Rams' choices of tackle Jason Smith (No. 2 overall), running back Isaiah Pead (No. 50 overall) and Hill (No. 15 overall) as the three worst picks made by the Rams relative to other players drafted at their positions.

Even more damning is that the Rams rank with the Lions and Raiders as the three worst teams at finding value in rounds 4 through 7. That's a sobering number considering the number of misses the Rams have had in the first round in that time (Barron, Kennedy, Hill, Carriker, Smith). But the Rams have had more success in the earlier rounds recently with players like Robert Quinn and Aaron Donald. Wven when they don't hit a home run, they avoided massive busts like Smith lately.

And the team's performance drafting in the later rounds might be getting a boost from some of the early returns on players taken recently. Cornerback E.J. Gaines was one of the steals of last year's draft in the sixth round, and other useful players such as defensive end Eugene Sims and running back Zac Stacy have also come in later rounds.

Though the Rams have drafted better in recent years than they did in the early 2000s, they still have a ways to go to catch up with the teams that rank at the top. Using the same numbers, Seattle, Indianapolis, Philadelphia, Green Bay and Pittsburgh rank as the top five teams in the league at drafting.

Those teams have combined for five Super Bowls and 49 playoff wins in that time.