This year, Giannis Antetokounmpo & James Harden have submitted awesome seasons. Both are deserving of MVP's, and in many years either would win. But, there can be only one.
And when you break it down, Giannis is somewhat clearly the MVP in my opinion. For posterity, this analysis was done when both HOU & MIL had played 80 games, so technically there are 2 games left for both teams.
First, let's just look at the stats. And at first glance it seems that this favors Harden.
When you look at raw per game stats, Harden has an edge. He's scoring 8.5 more points per game, and although his efficiency isn't quite as good as Giannis, it's still excellent - and for his volume and usage it equates to one of the best scoring seasons submitted.
Adding some of the advanced stats add to Harden's case (* = nba best):
Giannis: PER 30.7, WinShares 14.2, WS/48 .292*, BPM 10.7
Harden: PER 30.6, WinShares 14.8*, WS/48 .254, BPM 11.7*
Let's look at the team's performance:
Harden's team was struggling mightily - Houston (with everyone healthy) started the season 11-14. Since then, they have gone 41-14 to be at 52-28 with 2 games left. When injuries started happening to key players CP & Capela, Harden put the team on his back and turned the season around with unstoppable offensive performances. Harden has missed 4 games, in which Houston is 2-2 with wins at BKN & GSW, and losses at home vs POR & LAC. All 4 playoff teams (BKN maybe still).
The Bucks are 59-21. They have the best record in the league, clinched, so homecourt throughout the playoffs (and they just rested Giannis). They have a +9.1 point differential, which I believe places them in the top 8 all-time. The other 7 teams all won the championship (and are some of the all-time great teams). Giannis has been their undisputed best player. He's missed 9 games, They are 4-5 without him (so 55-16 with him!!). Without him their only "impressive" win was toronto without Kawhi - which isn't that impressive. The other wins were all against awful teams. They've lost to WAS, CLE, BKN, ATL, ORL. Some pretty bad teams in there.
In fact, when you dig a little deeper in the on/off court stats, you'll see that HOU is +3.1 net rating with Harden on the court vs off the court (they outscore their opponents by 3.1 points per game more), but MIL is +9 net rating with Giannis on the court vs off the court. In fact, if MIL has a +9.1 point differential, net rating basically attributes all of that positivity to Giannis (To compare Houston has a +4.5 point differential on the season, and doing the same math, if you take Harden off of Houston, they still clock in at +1.4, which is higher than MIL without Giannis). In other words, MIL go from an all-time great regular season team +9.1 to an average NBA team +0.1 without Giannis on the court based on the on/off stats & point differential. It makes sense to when you look at how they've performed in the games Giannis didn't play. To contrast, Houston goes from a good playoff team +4.5 with Harden to a mediocre playoff team +1.4 without him.
And in fact, when you look at the per game stats through another angle - per 36 - Harden's advantage there goes away as well.
The reason is because Harden has been playing 4 more minutes per game at 36.9 vs 32.9. That would make sense given that MIL has been blowing teams out (with a +9.1 point differential), and so Giannis hasn't had to play as much. In my view, these P36 numbers are more telling in this case than the per game numbers. Sure, you can use P36 to overvalue bench guys who don't get a lot of minutes. But both of these guys are getting 30+ minutes and are their team's best players, playing at all the most important times. Therefore, you can see that when you make this adjustment for how effective they are per minute on the court, you see that Giannis catches up, and in my opinion slightly passes Harden, especially given the slightly better efficiency. This is why also for the advanced stats although Harden had a league leading WinShares, Giannis had the league leading WinShares per 48 minutes.
So, IMO, when you look at things this way, and realize that a big part of the reason Giannis's per game stats are slightly worse than Harden's is because MIL has been so good that they have been blowing teams out and not needing to play Giannis as much (especially in the 4Q)... but when you adjust for that and look at how effective they are statistically P36 - you see that Harden's statistical edge vanishes.
Then you're faced with the fact that Giannis is a candidate for Defensive Player of the Year. He's a multi-positional monster who can guard anyone, on the perimeter to down low - even blocking Embiid in a recent game. The Bucks are about to drop a historic point differential and the league's best record. And Giannis isn't just the best player on the team, the Buck's second best player (Middleton... or is it Bledsoe??) is good. He made the all-star team. But Middleton will likely be the worst second-best player on a team that finishes the regular season with a 9+ point differential. He's also worse than Chris Paul (who to be fair did miss some games this season). Harden has improved defensively from someone who used to be a liability to a reasonable defender. But he isn't in the runnning for DPOY and won't make all-nba team defense, where GIannis definitely will.
One of the main Harden arguments is how he put them on their back and saved the season. That he did. But he was also on the team, fully healthy, while it was struggling early to the 11-14 start. While you can't pin that all on Harden by any stretch. As their best player, he has some culpability, and in a season where someone has the impeccable case that Giannis does, a minor ding like that is enough to cost Harden the MVP. Giannis is ding-free.
Another really interesting video that's about another topic (stat inflation) that helps compare stats from different years by normalizing a player's stats to the league averages. Scoring and pace have been up, so everyone's stats are up. What does this mean with regards to these two players?
When you adjust, Giannis is the only player to put up 28pts, 13rebs, 6ast - ever.
Harden does still hold the highest adjusted scoring ever by a hair over MJ & Kobe who are tied for 2nd.
So clearly, both players are submitting bonkers all-time statistical seasons. But when you look beyond offensive stats to their role on defense, to how well their teams have done AND how important the players has been to this success... I think Giannis separates from Harden a bit. This argument isn't to detract from what Harden has been doing. I just believe that when you look at everything as a whole and in context, as good as James Harden's season has been for the Rockets... Giannis's season has been better for the Bucks. And enough better than I believe he should be the MVP.