If the NBA season were a school year, we'd already be handing out first-quarter grades this week. So which players would deserve an A-plus for their early work in the 2014-15 campaign?

To address such questions, Jeremias Engelmann and I introduced an advanced metric last season: real plus-minus (RPM). It's a mathematical estimate of each player's true plus-minus contribution, adjusting for the strength of every on-court teammate and opponent. RPM gauges the impact of each player on his team's net efficiency (points per 100 possessions). And it yields separate metrics for offensive (ORPM) and defensive (DRPM) play, respectively.

From RPM, we can also generate wins above replacement (WAR), which takes into account each player's total possessions to estimate the number of wins he's generated for his team (above and beyond that of the typical "replacement player").

Here's the current RPM/WAR leaderboard:

It's not a bad list of All-NBA candidates through the season's first quarter. It also suggests some provocative takeaways, among them:

Harden's new commitment to defense appears to be real -- and it makes him a legitimate MVP candidate

Harden



James Harden's matador defense is the stuff of legend, not to mention viral YouTube videos. According to RPM, his reputation for atrocious D last season was fully justified: His defensive RPM value (minus-2.84) was among the league's worst. Even his brilliant offensive play couldn't completely offset the damage, as he was nowhere to be found among last season's total RPM leaders.

But Harden is one of several players -- together with DeMarcus Cousins, Rudy Gay, and Kyrie Irving -- who have taken their respective games to a whole new level after spending the summer with Mike Krzyzewski, Tom Thibodeau and the rest of the Team USA staff. And while no one is ever going to confuse the Bearded One with Tony Allen, it's clear that Harden has elevated his defensive play this season.

You can see it in the box score stats, where he has suddenly emerged as one of the game's most prolific shot-blockers in the backcourt (third among guards at 1.1 blocks per game) and climbed into the league's top 10 in steals (2.0 per game). You can see it even more clearly in his defensive RPM rating this season (1.82), quantitative evidence of a dramatic turnaround in overall defensive play.

On the strength of such improvement, Harden has quietly posted the second-highest WAR in the league thus far, and propelled the Rockets to their red-hot 16-5 start this season.

Anthony Davis has made "the leap"

Davis



Davis posted stellar box score stats last season, clocking in at 20.8 PPG, 10.0 RPG, 2.8 BPG and a 26.5 PER. But like most other second-year players, The Brow didn't really move the needle much in terms of his team's actual on-court performance. The mediocre Pelicans were nearly as "good" when Davis sat last season -- a surprising fact, perhaps, but one that's reflected in his lackluster 1.43 RPM during the 2013-14 campaign.

This season, though, Davis' beastly on-court impact is undeniable, and he's already risen to No. 4 in RPM. What's different? For one thing, he's become a more efficient offensive player, with more FG attempts inside, more trips to the foul line, and a strong bump in true shooting percentage (now a lofty 61.8). Davis has also begun to tap his full potential as a defensive force. He's again leading the league in blocked shots at nearly three per game, but even more importantly, he's getting into the right spots at the right time on both ends of the court.

According to RPM, Kevin Durant ascended to uber-stardom during his third NBA season, and Davis may be following closely in his footsteps.

Klay Thompson might be a bargain on his near-max contract

Thompson



Golden State turned down the chance to swap Klay Thompson for Kevin Love (in a multiplayer deal) this past offseason -- a non-move widely criticized around the league. Then the team raised more eyebrows by signing the 24-year-old to a quasi-max-level extension in October. After all, we're talking about a player who barely cracked the top 50 in RPM last season, with other advanced stats liking his game even less.

But the Warriors' brass saw Thompson's star potential, and he has already rewarded that faith by playing at an All-NBA level this season. He's currently ranked second in the league in RPM (7.36), right behind Curry (talk about a dynamic duo), and fourth in WAR (3.85).

Under the more creative offensive system ushered in by new Warriors coach Steve Kerr, Thompson is playing a much larger role. He's driving the ball more (nearly doubling his trips to the charity stripe), distributing it more (assists up more than 50 percent), and shooting it more often -- and at a higher percentage. And while his potential for lockdown wing defense has often been glimpsed in seasons past, Thompson's defensive prowess has been more evident this year, a development reflected in a steep rise in defensive RPM (currently 3.11, up from minus-0.17 last season).

If Thompson continues playing at this level going forward, his new contract may eventually be regarded as one of the league's real bargains.

Steph Curry is the league's true MVP thus far

Curry



The case is obvious, according to real plus-minus: Curry leads the league in RPM (7.42), he's second in offensive RPM (6.02), and -- perhaps most importantly -- he tops the WAR leaderboard. He's been the best player on the best team through the first 20 games of the NBA season.

What accounts for his stunning RPM-based impact? For starters, there's the jaw-dropping shooting efficiency. Curry boasts by far the highest true shooting percentage (62.9) of any high-usage player in the NBA. He leads the league in 3-pointers, and he's in the top 10 in scoring, assists and steals.

Curry is also much better on defense than many fans realize. His defensive RPM rating (1.40) indicates that he's actually been a plus defender so far this season.

LeBron is still figuring it out in Cleveland

James



He warned us not to expect greatness right away in Cleveland. He said it would take time -- just as it did four years ago in Miami -- for each teammate to find his ideal role, and it would take time for winning team chemistry to develop. But no one -- not even the King himself -- expected to "witness" a sharp drop-off in LeBron's own play during early 2014-15.

Last season, LeBron led the NBA with an otherworldly RPM of 9.08 points per 100 possessions. This season his RPM stands at "only" 4.49. That's still an All-Star-caliber number, but not even close to typical LeBron territory.

Most of the decline has been on the offensive side of the ball: LeBron's ORPM is down from 8.65 last season to 3.49 this season, and his true shooting percentage has slipped from 64.9 all the way to 56.6.

LeBron's drop in offensive efficiency is largely a function of his finding fewer easy scoring opportunities in the new Cleveland offense. Last year more than 44 percent of his shot attempts came within 5 feet of the basket -- at an astonishing 78 percent completion rate -- while this season such close shots account for only 38 percent of LeBron's FG attempts (at a sharply reduced 64 percent accuracy).

Folks in the psychology field often say, "The best predictor of future behavior is past behavior." And we know about LeBron's past behavior: He's been the best player in the game for several years running. So it would be unwise to bet against him returning to form in Cleveland as he adapts to his new environment. The smart money says he'll be back in the MVP conversation before this season winds to a close.