STATISTICALLY SPEAKING

When it comes to Jaromir Jagr, age is but a number.
He was 39 years old when he made his return to the NHL in 2011. By then, advanced stats were well on their way towards becoming a regular focus in the hockey world - and just as Jagr is elite in every other facet of the game, he quickly proved himself elite there, as well.

From 2011-17, Jagr has a CF% (Corsi-for) of 53.95 (advanced stats glossary and explainer below), and a relative CF% of +4.61, according to Corsica.hockey. That means that throughout his time across five different NHL teams, he was always a positive possession player. Since his return, his Corsi has never dipped below 50%.
Jagr may now be 45, but just this past season for the Florida Panthers, he had a CF% of 54.85, and a relative CF% of +6.12. And with an iCF (individual Corsi events for) of 223, he generated the third most Corsi events for in a single season since his return.
The Panthers were scoring while he was on the ice, too. In 2016-17, Jagr had a GF% of 55.79, and a relative GF% of +16.5. Since 2011, he's had a GF% of 56.95, and a relative GF% of +9.84.
So not only are his teams out-possessing their opponents when Jagr is on the ice, they're outscoring them, too.

While it's true that Jagr generally has benefited from more offensive zone starts, that's what you do with players who you want to score: you put them in a position to do just that. And Jagr's zone start ratio of 54.93% actually didn't leave him as sheltered as he has been in previous seasons.
The legend still has it.
But it's not just that. He also makes his teammates better.
Through 2016-17, Jagr's most common linemates on the Panthers were Aleksander Barkov, Jonathan Huberdeau and Jonathan Marchessault: three young forwards, then between the ages of 21-26. He played roughly 500 5v5 minutes on those lines; they were in between 56-58% CF.
Individually, Jagr made all three forwards better with his presence. With Barkov, the duo had a CF% of 57.08 - a jump of nearly 17 points for the Finn, according to Natural Stat Trick. Alongside Huberdeau, it was 55.61% - over 12 points more than Huberdeau had away from Jagr. And with Marchessault, their shared CF% was 57.52 - an increase of almost nine points for the younger player.
When skating alongside kids roughly 20 or more years younger than him, Jagr didn't just keep up with them: he made them better players.
And this was mere months ago. Slated to start in Calgary on a line with Kris Versteeg and young Sam Bennett, that's good news for Flames fans.
Every single stat Jagr has recorded - whether it be traditional, counting, or advanced - has pointed towards an elite athlete who has played at an incredibly high level throughout his entire career. That hasn't changed, and it isn't likely to.

Advanced stats glossary

CF% - Corsi For Percentage. Corsi is all shots on net, blocked shots, and missed shots, added together (basically, shot attempts). CF% is (Corsi For)/(Corsi For + Corsi Against). A CF% of 50% means a player has broken even; a CF% above 50% means he's a positive possession player, which is desirable to teams.
Relative CF% - CF%, but compared to the rest of the player's team. A positive relative CF% means that when a player was on the ice, his team did better than when he was off of it; a negative relative CF% means that his team was worse when the player was on the ice. It is used to differentiate whether a player was being carried by a good team or not; for example, a player can have a CF% over 50, but still have a negative relative CF%, meaning that even with the positive possession number, his team still perfors better without him on the ice.
iCF - Individual Corsi For. Every Corsi event an individual player has contributed to.
GF% - Goals for Percentage. Similar to CF%, GF% measures how many goals a player was on the ice for, versus against. It is (Goals For)/(Goals For + Goals Against). Like with CF%, 50% is breaking even, and above 50% means the team has been outscoring the opposition when the player on the ice.
Relative GF% - Same as relative CF%, but with GF%.
Zone Start Ratio - The percentage of zone starts a player experiences. Every faceoff occurs in one of three zones, and it can be telling when the coach chooses a specific player to take an offensive zone, or defensive zone, faceoff. Zone start ratio only pays attention to offensive and defensive zones. It is (Offensive zone start)/(Offensive zone start + defensive zone start). A ratio of 50% means the player is starting equally in both zones. Above 50% means he is starting more often in the offensive zone than the defensive zone.