I can't honestly choose from those two choices as one might or might not surpass the other depending on circumstances.
Not getting hit too much in out-and-out wars when you're young and a style that conserves energy are what it takes for longevity at this, imo.
RJJ and Hopkins comes to mind.....
RJJ was unstoppable for a decade but hop is just defying age and is getting extra credit for being competitive at 50..
To be an ATG you must have challenged yourself many times against the best opposition at the time, and that means the greatest in form fighters. Winning over famous fighters after they have past their primes counts for less.
Ducking the best at your own weight-classes means that you are probably not an ATG, and this will be counted in as a negative.
The more weight-classes you have cleaned out the better, and the more hall of famers at their peak you have fought the better.
Longevity at dominating one weight-class counts if all up-and-comers are fought, but if opposition at the weight-class is limited it is especially rewarded if you move up in weight to challenge the best at higher weight-classes.
How fights have been won also counts. Fights won over top competition in an impressive way counts for more. Knockouts count high, and a dominating decision win counts more than a split decision win.
Style is also counted in. Fighters who are more aggressively-minded have generally much shorter careers than defensively-minded fighters. Therefore defensively-minded fighters must normally have longer careers to be considered an ATG, while aggressively-minded fighters must normally have more knockouts to be considered an ATG.
If fights have been won because of bias judging the official win doesn't count as an ATG win.
Winning is not always necessary to get extra ATG points because great challenges count in themselves as positive, for example B-Hop's fight against Kovalev. So losing is not always a negative, but normally a loss requires a win in a rematch to settle the score and wipe out any negativity counted in towards ATG. However, a loss after moving up in weight-class to challenge another champion, is not necessarily a negative.
To answer your question so is longevity normally compared to knockouts, because as an ATG you should normally have either knockouts or longevity, and both counts for more. Peak performance is a must for all ATGs, and dominance depends on the level of opposition.
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Combination of both but ultimately, it's about who you beat, WHEN you beat them and who you lost to. Or else someone like Salvador Sanchez gets heavily penalized.
Resume has nothing to do with it? Resume has PLENTY to do with it. Anybody can look good fighting bums.
You become the best by beating the best. That's why resume is so important.
Every champion beats the best. Otherwise they would not be champs at all. And the longer they've been champs for, the more of the best they've beat.
This is what I'm saying, resume is era specific and you an only achieve ATG against the fighters in your era. Therefore it is worthless for a comparison and the "ALL TIME" part of it is totally false!
Some ATG's achieved the status without EVER facing a decent opponent!
Just Wanted to see everyones point of view...
It's a mixture of both to be a truly high ranking ATG. Take someone like Tyson, who is ranked in the bottom half of most people's top 50. He had an immense peak performance(s). He was the most feared man on the planet for 3-4 years and seen as the most dominant heavyweight ever. Then he had a slow ,decade long decline and he never managed to grab that spark again.
Then turn to Ali, in most people's eyes the greatest heavyweight of all time who had a brief period at the top as the "untouchable". He came back and lost a couple times, had his jaw broke and looked vulnerable...he looked human but then went on to win the title again and stay champion for an extended period of time when he was the best again but clearly past his best.
So it's a combination of the two.
"ATG" is an utterly worthless assessment for any boxer comparison at all.
It is/should be considered nothing more than an "honorary" title.
It is basically achieved observably by being the or one of the best boxers in your division in your era.
THAT^^^ is exactly how it's always been achieved period and there's really no other criteria is could be achieved by.
Resume has nothing to do with it. Proven by the fact that B level boxers today have better resumes than almost ALL ATG's did.
Resume has nothing to do with it? Resume has PLENTY to do with it. Anybody can look good fighting bums.
You become the best by beating the best. That's why resume is so important.
What makes an ATG is a great resume.
"ATG" is an utterly worthless assessment for any boxer comparison at all.
It is/should be considered nothing more than an "honorary" title.
It is basically achieved observably by being the or one of the best boxers in your division in your era.
THAT^^^ is exactly how it's always been achieved period and there's really no other criteria is could be achieved by.
Resume has nothing to do with it. Proven by the fact that B level boxers today have better resumes than almost ALL ATG's did.
I think the best ability at a peak performance is the most important in a H2H sort of way. Longevity is more a resume' building type of stat. I tend to favor H2H all time matchups personally.
Depends..
PEak dominance is kind of like a one hit wonder song, shines brightly for a moment and then gone, like Tyson.
Longevity like Evander Holyfeild and Ali winning and losing all the time isn't exactly great either.
There are only really 3 HW's in recent history (modern times) that satisfy both conditions.
Wladimir Klitschko
Vitali Klitshko
Lennox Lewis
They were both long lived AND peak dominant champions in a league of their own.