GIA Cut Grade
- Thread starter pwings
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In a nutshell - NO it is not equal.
Read more about it on this thread, and decide for yourself.
https://www.pricescope.com/community/threads/consumer-advisory-gia-cut-grade-rounding-problems.39401/
Rockdoc
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Garry, may I correct this?
"GIA Excellent can be AGS4 (AGS5 is theoretically possible, but we have not seen examples of this yet), based upon average proportions.
AGS 0 can be GIA Good, mostly because of GIA downgrading painting or digging of minor facets.
In the same way, HCA-1 can be GIA Good, because of the same reason.
We saw a GIA Poor that gets AGS1 for light performance (light return is not a grade of the AGS-report).
Confusion reigns."
Now my own comment:
Suppose that you can send your very smart kid to either of two schools, located in the same street. Both schools are reputable, but have a different way of reporting scores on exams.
The AGS-school has a score-system with 11 layers, while the GIA-school has one with 5 layers. Basically, if there are no mistakes in the correction of the exams, one could say that the top-grade of GIA conforms with the first 5 grades of AGS (0 to 4).
Now both schools sometimes make errors in correcting exams. However in the GIA-school, such an error has a more dramatic result, since you only have 5 possible scores. In the AGS-school, such an error of the school is clearly less dramatic.
There is even a reason why one school only has 5 grades, while the other one has 11. According to the GIA-school, in life, one cannot observe any professional difference within the same top-grade. I personally do not agree with that, and many others with me. Therefore, my kids are going to the other school.
Live long,
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JohnQuixote
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It's a problem if you want to subscribe to both schools. Some people have been looking for proportions combinations the two labs have in common in their top grade. In truth there are none, because GIA stereotypes brillianteering, and may downgrade any such diamond regardless of proportions sets.
Paul's school example is like GIA awarding all students who score >70% on a test the same grade of 'Excellent' - basically calling them equal. The kid with the 71% is the same as the kid with 100% in their eyes...
Meanwhile AGS would recognize those students differently - assigning 5 escalating grades between 70 and 100% to make distinctions between what they regard as different levels of achievement.
The problem, as Garry reports, is that GIA occasionally takes one of those kids who scored an 85% from AGS, tears his paper up and says he gets a 50%.
It's going to boil down to which school of thought you believe in.
Garry - what AGS0 have you encountered that were not GIA Ex? New metric (don't include those downgraded due to brillianteering stereotypes).
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Garry,
It is incorrect to dismiss the organisation of a school, because of one student getting the incorrect grade. This might be a clerical mistake, or an organisational mistake, or maybe the teachers just did not like the kid. It is clearly a mistake of the school, but they can work on that without basically changing the operation of the system.
I mean, you can clearly point out this example and show why this is an incorrect grade in their own system, and the school might understand this error, and correct it, without touching the basics of having 5 possible grades only.
In any case, any lab will make mistakes, but the effect is much bigger if you only have 5 in stead of 11 possible grades. This speaks for itself.
Live long,
It is incorrect to dismiss the organisation of a school, because of one student getting the incorrect grade. This might be a clerical mistake, or an organisational mistake, or maybe the teachers just did not like the kid. It is clearly a mistake of the school, but they can work on that without basically changing the operation of the system.
I mean, you can clearly point out this example and show why this is an incorrect grade in their own system, and the school might understand this error, and correct it, without touching the basics of having 5 possible grades only.
In any case, any lab will make mistakes, but the effect is much bigger if you only have 5 in stead of 11 possible grades. This speaks for itself.
Live long,
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Since we are in the process of showing analogical examples, how about this one:
Imagine the Olympics, the athletic events, 400 meters. 80,000 spectators in the stadion, looking at the race. Each runner has to run a lap once, every time in a race with just two runners. No chronometers allowed inside the stadion, only visible observation.
At the end, after all the runners have run, the public has to decide upon the results of the race.
Basically, this is the cut-study of GIA. Result: upon the observation of 80,000 people, we can decide that all the racers are placed into five categories, of which the top-category all get a gold medal of excellent.
AGS on the other hand works differently:
Each runner is examined in a lab, and his muscle-mass, VO2-max, his weight, length, reaction-time, and many other parameters are all measured. Then, these parameters are put into a virtual system, which calculates the theoretical time this runner can put on a 400 meter-lap. Then, there is a decision-process, which decides at which theoretical time, a runner is AGS-0, 1 or 2.
Neither system is perfect, but I clearly prefer the second system.
Live long,
Imagine the Olympics, the athletic events, 400 meters. 80,000 spectators in the stadion, looking at the race. Each runner has to run a lap once, every time in a race with just two runners. No chronometers allowed inside the stadion, only visible observation.
At the end, after all the runners have run, the public has to decide upon the results of the race.
Basically, this is the cut-study of GIA. Result: upon the observation of 80,000 people, we can decide that all the racers are placed into five categories, of which the top-category all get a gold medal of excellent.
AGS on the other hand works differently:
Each runner is examined in a lab, and his muscle-mass, VO2-max, his weight, length, reaction-time, and many other parameters are all measured. Then, these parameters are put into a virtual system, which calculates the theoretical time this runner can put on a 400 meter-lap. Then, there is a decision-process, which decides at which theoretical time, a runner is AGS-0, 1 or 2.
Neither system is perfect, but I clearly prefer the second system.
Live long,
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