Which NFL tacklers "rate" best?

Updated: May 31, 2002, 2:30 PM ET
By by Michael Hammer, STATS. Inc.
The Monsters of the Midway. The Steel Curtain. The Purple People Eaters. The Orange Crush.

Those titles call to mind some of the most dominant defenses in the history of the NFL, units that propelled their respective teams to lofty playoff heights. Glorious nicknames aside, it always has been fairly easy to quantify the contribution of a defensive unit to a team's overall success. What continues to be more challenging, however, is to quantify the contribution of a defensive player to his unit's overall success. Interceptions and sacks are the only "official" statistics tracked for individual defenders, but these stats only reflect defensive performance on a handful of plays. While one may choose to consider "unofficial" tackle and assist totals, even those fall short of providing a true indication of a player's overall contribution. For example, on paper, an assist on a tackle 30 yards down field is of equal weight to an assist of a tackle made in the backfield.

Among current NFL defenders, Baltimore's Ray Lewis deservedly grabs plenty of votes as for being heads above the rest when it comes to making plays, especially the big, game-turning type plays. Still, quite a controversy raged last season when Steelers running back Jerome Bettis suggested that Takeo Spikes of the Bengals was every bit as good as Lewis. Is there any way to evaluate such claims, given the scarcity of available data? Are the total tackles and assists all we have to go on, and how well do they reflect meaningful on-field performance?