Steve Ilardi and Jeremias Engelmann have written an entertaining and enjoyable (for a Spurs fan) stats-based article comparing Tim Duncan and Kobe Bryant for ESPN Insider ($), and use Predictive Real Plus-Minus (RPM) to judge between the two.
They begin by giving the nod to Bryant on the offensive side of the ball:
Kobe logged the higher Offensive RPM for 15 consecutive seasons from 1999-2000 through 2014-15. Over that span, Kobe boasts a huge lead in the metric, with an average of 5.2 to Duncan's 1.8.
And they show that Duncan is the superior defender:
Even though Kobe has somehow earned more career All-Defensive honors than Duncan (nine to eight, if you're keeping score at home), Bryant's true defensive impact pales in comparison.
To put it bluntly, Kobe's defense is highly overrated. According to DRPM, he hasn't had a large positive impact on defense in a single one of the past 15 seasons. He actually has been among the league's poorest defensive wings for five years running.
But that doesn't mean that Tim and Kobe end in a 1-1 tie.
One of the most compelling features of RPM is the metric's ability to compare the relative impact of each player's offensive and defensive contributions. And that's important, because even though offense is usually what grabs our attention, defensive play is every bit as vital to team success
And then they look at total RPM (which combines both offense and defense) which brings us to the money line:
With the exception of two seasons (2005-06 and 2007-08) at the peak of Kobe's prime, Duncan has had the higher RPM value -- the greater positive impact on the game -- in each of their other seasons.
For most of those seasons, it hasn't even been that close. Since 1999, Duncan has had an average RPM of 6.97 to Kobe's 3.75, a decisive edge to Duncan.
I must admit to having a soft spot in my heart for the phrase "decisive edge" but they don't stop there. In fact, they go on to conclude that Duncan is, "...quite simply the best player of his generation."
I couldn't have put it better myself.