Investment analysts are fond of saying past performance is no guarantee of future results.
The same maxim is not applied nearly as often in professional sports.
And this explains why some are saying the Canucks got a bad deal in trading veteran centre Ryan Kesler to the Anaheim Ducks.
Writing on The Score website, Thomas Drance characterized the Vancouver Canucks as one of the losers in the NHL draft, dismissing the deal as "the lopsided Kesler trade".
"Vancouver netted poor value in a trade involving a star player with a division rival," Drance declared. "It's tough to come back from that."
What Drance fails to recognize is that once NHL forwards enter their 30s, their point totals often stagnate. Kesler turns 30 on August 31.
Canucks management, unlike many hockey writers, recognize that in their industry, past performance is indeed no guarantee of future results.
Let's just look at the records of some well-known players.
Daniel Sedin turned 30 before the 2010-11 season, when he had his best year: 41 goals, 63 assists, and 104 points.
The next year, hobbled by an elbow to the head from Duncan Keith, Daniel Sedin's output fell to 30 goals and 67 points. Since then, he's scored 28 goals in two seasons.
Brother Henrik Sedin's scoring peaked when he was 29 years old in 2009-10 when he posted 29 goals and 112 points.
After turning 30, he fell to 94 points and then dropped to 81 points the following year. Last year, he registered 50 points at the age of 33.
Last November, former general manager Mike Gillis re-signed the Sedins to four-year contract extensions, which was cheered at the time by many fans.
In light of what's happened since then, perhaps Gillis also was under the mistaken impression that past performance offered a guarantee of future results.
There's no denying the Sedins' character or their contributions to the community, most notably in a generous $1.5-million gift to B.C. Children's Hospital.
But it's also hard to ignore that the Canucks missed the playoffs last year, thanks in part to the Sedins' inability to get on the scoresheet.
As an NHL player, Canucks president Trevor Linden peaked even earlier than the Sedins, scoring his highest point total in 1995-96 at the age of 25.
Linden never came close to matching the 33 goals and 47 assists of that season.
It was his sixth 30-goal season, but after that, his highest one-season total was 19 in 2002-03. Playing in the NHL takes a toll on forwards.
This was also clear in the case of Pavel Bure, the only Canuck in the Hall of Fame.
He had five seasons in which he scored between 51 and 60 goals. None occurred in seasons that started after he turned 30.
Bure's peak performance afterward was 22 goals and he only scored 53 of his 437 NHL goals in seasons that began after his 30th birthday.
Four of Howe's 40-goal seasons occurred in his 20s. Only one came in his 30s, and that happened in the high-scoring expansion era of the late 1960s.
Meanwhile, Wayne Gretzky had only one 100-point year in a season that began after he turned 31. He never scored 40 goals in his 30s, but managed this feat every year he was in his 20s, maxing out at 92 goals in the 1981-82 season.
One of the few exceptions to this rule was Phil Esposito, who scored 68 goals and then 61 goals in his first two full seasons after turning 30.
Esposito still managed four more 30-goals seasons and one 40-goal season in his career. But he never matched his output during his prime years in seasons that began for him from the ages of 26 to 32.
Keep in mind that Esposito often stood in the slot waiting for passes. He didn't play the same gritty style as Kesler, who's been hobbled by injuries in recent years.
Based on the examples above, the odds are that Kesler's best NHL days are behind him and Canucks general manager Jim Benning probably traded him at the perfect time.
In return for their star centre, the Canucks received Nick Bonino, a 26-year-old centre who scored more points last year than Kesler did.
Benning and Linden haven't purged all the oldtimers.
The Canucks still have four forwards in their 30s: the Sedins, Alex Burrows, and Chris Higgins. There are also three defenceman on the roster over the age of 30: Kevin Bieksa, Andrew Alberts, and Dan Hamhuis.
They're all probably feeling a little less complacent after what transpired over the past couple of days.