VCE Stuff => Victorian Technical Score Discussion => Topic started by: paulsterio on July 09, 2012, 12:50:30 am
Title: Guide to how Study Scores and ATARs are calculated!
Post by: paulsterio on July 09, 2012, 12:50:30 am
So recently, the amount of threads that are around asking about how Study Scores and ATARs are calculated have been numerous, so I hope this will be a be all and end all guide to those questions. This thread assumes that you have a good understanding of statistics and probability which is covered in Mathematical Methods - even if you don't, it will still make a lot of sense, as long as you skip over the mathematical parts.
Study Score
Your study score is a normally (Gaussian) distributed number which represents your performance in comparison to everybody else who did your subject that year. It is a probability density function with a mean of 30 and a standard deviation of 7. Essentially, the cut off for the Study Score is 50, which means that even if you are the best student in the state by a massive margin, you will still be awarded a 50.
A study score of 30 means that you are the median student in the state, approximately 50% of students are worse than you and 50% of students are better than you. Other commonly asked about numbers are 35 (top 22% of the state), 40 (top 9% of the state) and 45 (top 2% of the state) - note that these are only for studies which have a high number of enrollments, studies with fewer students may not be perfectly normally distributed.
Scaling
Scaling refers to a constant amount added or subtracted to the mean study score (30) - this means that its effects will always be greatest around 30 and it will be diluted as you move up or down, away from 30. Essentially scaling is introduced in order to reflect the amount of competition in the different studies. Certain studies, such as Specialist Maths (for example) have a much higher level of competition than a study such as Further Maths - because the Specialist Maths students are better at their subject than the Further Maths students usually are. This is why a student that is in the top 2% of Specialist Maths students is deemed to be better than a student in the top 2% of Further Maths students.
This is why Specialist Maths is then scaled up, whereas Further Maths is then scaled down.
How are Study Scores calculated
Study Scores are calculated by looking at the distribution of each of your three Graded Assessments (GAs). Every subject will have three GAs, each weighted differently depending on the subject. If the subject has one exam, the GAs will be such that - GA1 is Unit 3 SACs, GA2 is Unit 4 SACs and GA3 is the exam. Subjects with two exams will have one GA which represents combined SACs - which means that for these subjects, there are no Unit 3 SACs or Unit 4 SACs, they are all summed up as one mark.
So what happens is that you will get an arbitrary number for each GA which will represent your mark for the section. Usually for the exams, it will be your Exam mark, in SACs, it will be your scaled SAC mark. Now VCAA will plot your all the marks for a particular GA on a normal distribution and standardise it so that you get a Z-score - this is done by finding the mean and the standard deviations of the exam mark and using the formula to standardise (Z = (X-m)/o).
VCAA will then do the same thing with all of your three GAs, and will end up with three Z-scores. It will then do a weighted sum of the three scores and come up with the Z-score for your Study Score - which they will then "un-standardise" by introducing the mean of 30 and standard deviation of 7.
You might ask why they decided to use a mean of 30 and a standard deviation of 7. Well I think this is purely because 50 will then be (around) 3 standard deviations of the mean and 50 is a convenient number to use. (99.7% of values are within 3 SDs of the mean).
How are SAC GAs calculated
SAC GAs are often where most students get lost - and it is probably because most are not familiar with it.
First of all, what is important here is your overall SAC rank. This means that if you are ranked first, it doesn't matter if you are ranked first by a big margin or by a small margin. If you are ranked first, you are ranked first.
So now, say you are ranked nth. What VCAA will do is they will give you the nth exam mark in your cohort as your SAC mark.
So if there are three students, Thushan, Dan and Paul in a cohort and they each get an average SAC mark of 100, 70, 60 respectively, this means that Thushan will be ranked 1, Dan will be ranked 2 and Paul will be ranked 3. Say they all sit the exam, and on the exam day, Dan's beard has grown so much that he can't see his exam paper anymore, thus, their exam marks are 100, 20, 70.
This means that for the SAC GA - Thushan will get 100, Dan will get 70 and Paul will get 20. Shadows came across this video created by 'jpbreheny13878' on YouTube, which might be worth watching if you're still confused. Particularly on the point of what role do raw sac marks have to play in the statistical moderation process, do also take a read of the discussion later in this thread, especially the posts Re: Guide to how Study Scores and ATARs are calculated! onwards as they provide a bit more detail in addition to this post and the video.
That video was posted by shadows in this thread SAC SCALING EXPLANATION But isn't this unfair
Yes, in some way or another this is unfair, especially if you have a small cohort, however, they need a way of standardising SACs so that students who go to good schools aren't disadvantaged. For example at MHS, it is apparently very difficult to get 100% on Specialist Maths SACs, but if I go to some not-so-well-off school, it might be a breeze. So if it was all raw marks, I would just go to that not-so-well-off school - not to mention schools would then purposely set easy SACs so that their students would dominate.
It becomes a complicated system if we just consider the raw marks.
How is the ATAR calculated
The ATAR is calculated by taking your English (or EL/Lit/ESL) score and adding it to your top three scaled scores, then adding 10% of the highest two of your remaining scores and this becomes the aggregate. The aggregate is then plotted as a cumulative probability density function and you are given the number that corresponds to your aggregate.
This means that if you have gotten an ATAR of 98.50, your aggregate is better than 98.50% of the state.
Questions? Post below!
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: jmosh002 on July 09, 2012, 12:52:42 am
Thanks Paul this is great ! :)
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Jenny_2108 on July 09, 2012, 01:02:05 am
So if there are three students, Thushan, Dan and Paul in a cohort and they each get an average SAC mark of 100, 70, 60 respectively, this means that Thushan will be ranked 1, Dan will be ranked 2 and Paul will be ranked 3. Say they all sit the exam, and on the exam day, Dan's beard has grown so much that he can't see his exam paper anymore, thus, their exam marks are 100, 20, 70.
This means that for the SAC GA - Thushan will get 100, Dan will get 70 and Paul will get 20.
I dont understand this part. If Dan gets 20 in the exam, its suppose that his study score will be down right? Why is it still 70? Btw, Paul's exam score is 70 which is not very different from the SAC mark, why does he get 20?
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Scooby on July 09, 2012, 01:13:27 am
How is it possible to get 200/200 scaled for the SAC GA even if no one in your cohort got 100% for the exam? ???
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Lasercookie on July 09, 2012, 01:14:35 am
I dont understand this part. If Dan gets 20 in the exam, its suppose that his study score will be down right? Why is it still 70? Btw, Paul's exam score is 70 which is not very different from the SAC mark, why does he get 20?
His study score will probably take a large hit, study scores are composed of 3 graded assessments (with various weightings as Paul explained), the 70 was just for the graded assessment relating to SACS, not the exam.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Phy124 on July 09, 2012, 01:23:52 am
I dont understand this part. If Dan gets 20 in the exam, its suppose that his study score will be down right? Why is it still 70? Btw, Paul's exam score is 70 which is not very different from the SAC mark, why does he get 20?
What he's saying is that; as Paul is ranked third he will get the 3rd highest exam score as his scaled SAC score, which happened to be the 20 scored by Dan.
Thushan was ranked first so he will get the top exam mark as his SAC score which was 100 (scored by himself).
Finally, Dan will get the second highest exam mark as his scaled SAC score, which was 70 (scored by Paul).
So you end up with
Student Exam SAC (scaled) Thushan 100 100 Paul 70 20 Dan 20 70
Assuming it was just two equally weighted GA's Paul and Dan would end up with the same study score, quite a low one at that due to Dan's poor exam performance not only impacting himself, but Paul as well due to SAC ranking and consequent scaling.
Well I think this was what he was getting at anyway.
Also, it would not surprise me if the scaling system for SACs was more complicated than this, but this is as close as we'll get to a description of how it works.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: paulsterio on July 09, 2012, 01:55:10 am
How is it possible to get 200/200 scaled for the SAC GA even if no one in your cohort got 100% for the exam? ???
It's rounding and other effects - it happenned with my school for spesh as well, I was ranked one and got 100 for SACs, but the highest exam mark was a little below 100%, but when rounded off slightly, it was enough to give me the 33.3333% for SACs.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: spectroscopy on July 09, 2012, 10:38:04 am
It's rounding and other effects - it happenned with my school for spesh as well, I was ranked one and got 100 for SACs, but the highest exam mark was a little below 100%, but when rounded off slightly, it was enough to give me the 33.3333% for SACs.
who rounds it off? LOL and what happens if there are two people ranked first with 100% on every sac, and on the exam one gets higher then the other(both are the top scores), who gets the higher score?
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Fishyiscool on July 09, 2012, 11:45:39 am
now im gonna spend the rest of my vce poring over this D: Thanks for the explanation though :)
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: max payne on July 09, 2012, 11:59:17 am
It's rounding and other effects - it happenned with my school for spesh as well, I was ranked one and got 100 for SACs, but the highest exam mark was a little below 100%, but when rounded off slightly, it was enough to give me the 33.3333% for SACs.
who rounds it off? LOL and what happens if there are two people ranked first with 100% on every sac, and on the exam one gets higher then the other(both are the top scores), who gets the higher score?
The one who got a higher exam score obviously
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: spectroscopy on July 09, 2012, 12:10:10 pm
just realised how dumb that sounded fml
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Stick on July 09, 2012, 12:13:48 pm
Very nice explanation, Paul, thank you very much.
Just to clarify something. With the SAC scaling, does that mean that if you're in an average cohort, but with a strong upper quarter or so, and you sit in that section that you're not really disadvantaged by having a slightly lower rank? I'm in this current situation where I'm sitting in an average strength cohort of 97 for Further, but the top 20 students are really strong. So if I was to sit anywhere between ranks 1 and 20 and all of us in that section aced the exams, then we would all do really well, right? I'm thankful that I'm currently holding rank 1 but I guess I would like to know that it's not the end of the world if I drop a couple of marks on the next two SACs. :)
Also, I think I can tell you why the mean sits at 30, rather than 25. Basically, there's a lot of students that enrol in subjects at the start of the year and then do absolutely nothing, meaning there is a very large cluster of outliers that sit at a study score of 0. I think VCAA moves the standard distribution in such a way that even if you do really badly in all of your assessments, you will most likely receive a study score of 10 for actually completing the study. Hence, the mean is slightly bumped up.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: paulsterio on July 09, 2012, 12:34:56 pm
Just to clarify something. With the SAC scaling, does that mean that if you're in an average cohort, but with a strong upper quarter or so, and you sit in that section that you're not really disadvantaged by having a slightly lower rank? I'm in this current situation where I'm sitting in an average strength cohort of 97 for Further, but the top 20 students are really strong. So if I was to sit anywhere between ranks 1 and 20 and all of us in that section aced the exams, then we would all do really well, right? I'm thankful that I'm currently holding rank 1 but I guess I would like to know that it's not the end of the world if I drop a couple of marks on the next two SACs. :)
Also, I think I can tell you why the mean sits at 30, rather than 25. Basically, there's a lot of students that enrol in subjects at the start of the year and then do absolutely nothing, meaning there is a very large cluster of outliers that sit at a study score of 0. I think VCAA moves the standard distribution in such a way that even if you do really badly in all of your assessments, you will most likely receive a study score of 10 for actually completing the study. Hence, the mean is slightly bumped up.
You're welcome, but OK - you're absolutely right, you should not worry at all. The truth is, if you're ranked, say, 5th, you'd have to rely on the fact that there are 5 students (and you may be one of those five or you may not be) who will perform really well on the exam, because you will get the 5th highest exam mark as your own SAC GA mark. Whatever happens below you, doesn't really matter. For example, if you're ranked 5th in a cohort of 5 students, then you will get the 5th ranked exam mark as your SAC mark - like I have just explained. However, let's say you add in another 50 students below those 5, it still won't matter, you will still get the same SAC GA mark give that - 1) those 50 students don't rank within the top 5 and 2) those 50 students don't score higher than the other 5 on the exam.
You might be right, but essentially nobody gets a Study Score of 0, even if you don't do the exam. To be honest though, I don't know of anyone with a study score of below 25 up the top of my head - so I won't be able to tell you. Setting the mean at 25 wouldn't work though, because 3 SDs from the Mean will be 46, unless they adjust the SD to 8-ish, but hmm, it probably doesn't matter.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Fishyiscool on July 15, 2012, 12:41:43 am
Question: what about sac marks for subjects with two exams? Does your rank from the average of both exams get taken into account? :s And also, essentially your exam mark will always be your exam mark? Stuff up the exam and you're screwed? All the work you put in for sacs benefits someone else in the cohort? :s
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: ktrah on July 15, 2012, 01:00:18 am
This means that if you have gotten an ATAR of 98.50, your aggregate is better than 98.50% of the state.
Does that mean if you get an ATAR of 65, your aggregate is better than 65% of the state? If so, how come 65 is around the average? I've never quite understood why it's not 50 ???
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: pi on July 15, 2012, 01:21:53 am
This means that if you have gotten an ATAR of 98.50, your aggregate is better than 98.50% of the state.
Does that mean if you get an ATAR of 65, your aggregate is better than 65% of the state? If so, how come 65 is around the average? I've never quite understood why it's not 50 ???
It's percentiles. My understanding is that <30 doesn't count for the same amount as percentiles as between say 60-90 ATAR.
I'm not sure on the specifics though, good question, I'm interested too :)
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: FlorianK on July 15, 2012, 09:46:17 am
Just to clarify something. With the SAC scaling, does that mean that if you're in an average cohort, but with a strong upper quarter or so, and you sit in that section that you're not really disadvantaged by having a slightly lower rank? I'm in this current situation where I'm sitting in an average strength cohort of 97 for Further, but the top 20 students are really strong. So if I was to sit anywhere between ranks 1 and 20 and all of us in that section aced the exams, then we would all do really well, right? I'm thankful that I'm currently holding rank 1 but I guess I would like to know that it's not the end of the world if I drop a couple of marks on the next two SACs. :)
Also, I think I can tell you why the mean sits at 30, rather than 25. Basically, there's a lot of students that enrol in subjects at the start of the year and then do absolutely nothing, meaning there is a very large cluster of outliers that sit at a study score of 0. I think VCAA moves the standard distribution in such a way that even if you do really badly in all of your assessments, you will most likely receive a study score of 10 for actually completing the study. Hence, the mean is slightly bumped up.
You're welcome, but OK - you're absolutely right, you should not worry at all. The truth is, if you're ranked, say, 5th, you'd have to rely on the fact that there are 5 students (and you may be one of those five or you may not be) who will perform really well on the exam, because you will get the 5th highest exam mark as your own SAC GA mark. Whatever happens below you, doesn't really matter. For example, if you're ranked 5th in a cohort of 5 students, then you will get the 5th ranked exam mark as your SAC mark - like I have just explained. However, let's say you add in another 50 students below those 5, it still won't matter, you will still get the same SAC GA mark give that - 1) those 50 students don't rank within the top 5 and 2) those 50 students don't score higher than the other 5 on the exam.
You might be right, but essentially nobody gets a Study Score of 0, even if you don't do the exam. To be honest though, I don't know of anyone with a study score of below 25 up the top of my head - so I won't be able to tell you. Setting the mean at 25 wouldn't work though, because 3 SDs from the Mean will be 46, unless they adjust the SD to 8-ish, but hmm, it probably doesn't matter.
One guy in my year level got a 5 in Business Management and he sat the exam.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: WhoTookMyUsername on July 15, 2012, 10:53:06 am
it includes all students of the VCE age, even those who have dropped out of school, failed or otherwise; such that a 50 ATAR is better than 50% of the state, but probably only better than 30% of the state who has done VCE
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: TheMirrorMan on July 15, 2012, 01:24:51 pm
I'm a bit confused about the relationship between your SAC ranking and your study score. Does that mean that if you're 1st in your cohort in the SACs and bomb on your exam you'll still get the exam score of the person who got the highest mark in your cohort for the exam?
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Somye on July 15, 2012, 06:45:14 pm
You'll get their exam score as your SAC mark, but keep your own exam mark But this probably means that they'll still get a higher score overall, unless they had a horrible ranking
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: thushan on July 15, 2012, 08:27:41 pm
In a nutshell:
Your exam score remains your exam score.
If you are rank x in SACs, YOUR SAC score, when SCALED, will REFLECT (be equivalent to) the exam scores of the person who gets rank x in your school IN THE EXAM. Therefore, your SAC rank will remain as rank x.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Truck on July 15, 2012, 08:31:16 pm
Are you certain that your SAC score will directly correlate with the exam scores the cohort achieves? I only ask because I think there's a few more factors involved, i.e. I was under the impression the general GAT score of a school can help push scores up?
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: paulsterio on July 15, 2012, 08:56:39 pm
Are you certain that your SAC score will directly correlate with the exam scores the cohort achieves? I only ask because I think there's a few more factors involved, i.e. I was under the impression the general GAT score of a school can help push scores up?
A number of factors can play in the moderation of SAC scores, that's right, but nobody apart from VCAA knows how that works - but truth to be told, I know someone with a 98.95 ATAR who wagged the GAT :P
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Truck on July 15, 2012, 09:11:47 pm
Are you certain that your SAC score will directly correlate with the exam scores the cohort achieves? I only ask because I think there's a few more factors involved, i.e. I was under the impression the general GAT score of a school can help push scores up?
A number of factors can play in the moderation of SAC scores, that's right, but nobody apart from VCAA knows how that works - but truth to be told, I know someone with a 98.95 ATAR who wagged the GAT :P
Yeah, I wasn't suggesting the GAT matters on an individual level (unless you miss your exams), more that the average GAT score for the school, if good, can also push up average SAC scores.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: thushan on July 15, 2012, 09:34:43 pm
Are you certain that your SAC score will directly correlate with the exam scores the cohort achieves? I only ask because I think there's a few more factors involved, i.e. I was under the impression the general GAT score of a school can help push scores up?
A number of factors can play in the moderation of SAC scores, that's right, but nobody apart from VCAA knows how that works - but truth to be told, I know someone with a 98.95 ATAR who wagged the GAT :P
Yeah, I wasn't suggesting the GAT matters on an individual level (unless you miss your exams), more that the average GAT score for the school, if good, can also push up average SAC scores.
Yup, GAT can affect SAC scores, but apparently to a VERY minimal extent.
What I said was a simplification. This is the reason I said "reflect" rather than "be equal"
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Truck on July 15, 2012, 09:51:14 pm
Are you certain that your SAC score will directly correlate with the exam scores the cohort achieves? I only ask because I think there's a few more factors involved, i.e. I was under the impression the general GAT score of a school can help push scores up?
A number of factors can play in the moderation of SAC scores, that's right, but nobody apart from VCAA knows how that works - but truth to be told, I know someone with a 98.95 ATAR who wagged the GAT :P
Yeah, I wasn't suggesting the GAT matters on an individual level (unless you miss your exams), more that the average GAT score for the school, if good, can also push up average SAC scores.
Yup, GAT can affect SAC scores, but apparently to a VERY minimal extent.
What I said was a simplification. This is the reason I said "reflect" rather than "be equal"
Echhh, this is slightly worrying for me I guess.
In a subject like Chemistry, if I get an A+ on both of my exams (low to mid) but I'm ranked, at MHS, maybe in about the middle of the cohort, what kind of study score could I be looking at?
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: pi on July 15, 2012, 09:57:36 pm
Are you certain that your SAC score will directly correlate with the exam scores the cohort achieves? I only ask because I think there's a few more factors involved, i.e. I was under the impression the general GAT score of a school can help push scores up?
A number of factors can play in the moderation of SAC scores, that's right, but nobody apart from VCAA knows how that works - but truth to be told, I know someone with a 98.95 ATAR who wagged the GAT :P
Yeah, I wasn't suggesting the GAT matters on an individual level (unless you miss your exams), more that the average GAT score for the school, if good, can also push up average SAC scores.
Yup, GAT can affect SAC scores, but apparently to a VERY minimal extent.
What I said was a simplification. This is the reason I said "reflect" rather than "be equal"
Echhh, this is slightly worrying for me I guess.
In a subject like Chemistry, if I get an A+ on both of my exams (low to mid) but I'm ranked, at MHS, maybe in about the middle of the cohort, what kind of study score could I be looking at?
Mid-low 40s, possibly 42-45 :)
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: duhherro on July 18, 2012, 07:04:23 pm
So essentially...does that mean your own sacs don't really mean much if you dominate your own exam and will just use the person ranked above you his/her exam mark as YOUR sac mark? So it is possible to even get a lower SAC mark if the person ranked above you did worse in the exam than your SAC average.
and also, what happens if your SACs are calculated differently? Like there are the 10% SACs, some 40% ones etc, in the end is it just the average of ALL your sacs combined out of a 33% ?
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: monkeywantsabanana on July 19, 2012, 11:48:11 am
So now, say you are ranked nth. What VCAA will do is they will give you the nth exam mark in your cohort as your SAC mark.
So if there are three students, Thushan, Dan and Paul in a cohort and they each get an average SAC mark of 100, 70, 60 respectively, this means that Thushan will be ranked 1, Dan will be ranked 2 and Paul will be ranked 3. Say they all sit the exam, and on the exam day, Dan's beard has grown so much that he can't see his exam paper anymore, thus, their exam marks are 100, 20, 70.
This means that for the SAC GA - Thushan will get 100, Dan will get 70 and Paul will get 20.
Will Paul still obtain a higher SS than Dan?
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Somye on July 19, 2012, 02:36:26 pm
If the 2 GA's were weighted equally, then they'd have the same score, because Dan's poor exam result affects both him and Paul
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: brenden on July 19, 2012, 06:35:18 pm
I think this should be stickied. And maybe there should be a rule "Don't ask for predictions unless you've read Paul's guide, looked at the grade distributions and given it a go yourself".
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: pi on August 08, 2012, 01:56:28 pm
I think this should be stickied. And maybe there should be a rule "Don't ask for predictions unless you've read Paul's guide, looked at the grade distributions and given it a go yourself".
Stickied for added effect.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: FlorianK on August 12, 2012, 11:49:48 am
Hey Florian, there are sections A and B. Which one is text response and context response?
We are writing the same Exam as the english kids - basically.
Section A is excactly the same - same questions for every single book (Text response) Section B is the same question as English, but we only need to study 1 book Section C is the same piece we have to analyse, but we have to summarise the article first in noteform and we get judged on it.
Section A Text response 40marks Section B Context 30marks Section C Note-taking 15marks Text Analysis 15marks
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Jenny_2108 on August 12, 2012, 08:38:19 pm
Hey Florian, there are sections A and B. Which one is text response and context response?
We are writing the same Exam as the english kids - basically.
Section A is excactly the same - same questions for every single book (Text response) Section B is the same question as English, but we only need to study 1 book Section C is the same piece we have to analyse, but we have to summarise the article first in noteform and we get judged on it.
Section A Text response 40marks Section B Context 30marks Section C Note-taking 15marks Text Analysis 15marks
Section B: we only need 1 book? My school studies a book and a film, can I give evidence from both? Section C: I thought English is harder and they have to compare 2 articles while ESL is easier and only 1 article?
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: paulsterio on August 14, 2012, 09:07:43 am
Section B - yes you're allowed to give evidence from both if you wish
Section C - I don't know - they don't really say that ESL is easier per se - it's just two different tasks - I think the stimulus is the same.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: brenden on August 14, 2012, 09:10:19 am
Paul, if you receive the equivalent exam mark for your sac mark, why then are the graphed exam marks normally distributed and the sac marks are skewed?
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: vashappenin on October 10, 2012, 04:58:34 pm
I don't know if it was discussed previously in this post, but I'll ask anyway, because I'm still a little confused. If Thushan, Dan and Paul's sac scores were 90, 70 and 60 respectively for SACS, but for the exam Dan got 95, Paul got 85 and Thushan got 80. Would that mean that because he was rank 1 for SACs, Thushan's SAC score would now be 95? And does that mean that Thushan's exam GA score will still be 80? This is so confusing! Please correct me if I'm wrong :S
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: brenden on October 10, 2012, 05:25:51 pm
I don't know if it was discussed previously in this post, but I'll ask anyway, because I'm still a little confused. If Thushan, Dan and Paul's sac scores were 90, 70 and 60 respectively for SACS, but for the exam Dan got 95, Paul got 85 and Thushan got 80. Would that mean that because he was rank 1 for SACs, Thushan's SAC score would now be 95? And does that mean that Thushan's exam GA score will still be 80? This is so confusing! Please correct me if I'm wrong :S
You are correct.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Vicky95 on October 10, 2012, 07:55:44 pm
So basically being ranked 1 in a strong cohort accounts for naught if the same student does not perform equally well in the exam.
Whereas a student who is ranked, say 10th in the cohort and does exceptionally well in the exam will now ace overall as his SAC GA score now gets automatically scaled up.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Truck on October 10, 2012, 07:58:04 pm
So basically being ranked 1 in a strong cohort accounts for naught if the same student does not perform equally well in the exam.
Whereas a student who is ranked, say 10th in the cohort and does exceptionally well in the exam will now ace overall as his SAC GA score now gets automatically scaled up.
pretty much.
a while back our chemistry and maths methods teachers showed us a list of their prior years class, and what grades each student got to get their specific study score (to help give us an indication etc). There was not a single student, in either chemistry or Maths methods, who had a SAC score that was lower then their exam score(s) - at worst they were the same, at best higher. this was at MHS so maybe it's different at other schools, but i doubt it'd be any different at macrob :).
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Vicky95 on October 10, 2012, 08:05:44 pm
I should stop getting nervous and just aim to do my best! Que sera sera...
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Vicky95 on October 10, 2012, 08:10:31 pm
Another quick question - I've been hearing how SAC scores get scaled up? So a student getting say 100/100 can't expect any scaling - go any higher than that? Is that his max SAC score?
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: brenden on October 10, 2012, 08:24:06 pm
So basically being ranked 1 in a strong cohort accounts for naught if the same student does not perform equally well in the exam.
Whereas a student who is ranked, say 10th in the cohort and does exceptionally well in the exam will now ace overall as his SAC GA score now gets automatically scaled up.
No this counts for a lot. The student will get the highest exam score as their SAC score. The 10th student will still do exceptionally well however his SAC GA depends on the 10th highest exam score.
Another quick question - I've been hearing how SAC scores get scaled up? So a student getting say 100/100 can't expect any scaling - go any higher than that? Is that his max SAC score?
Yep. The SAC scores are equivalent to exam scores. I've never seen someone get more than 100% on any VCAA exam.
And I'm not meaning to be prejudicial at all but I wouldn't worry about your ranking and SAC score etc etc going to MacRob.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Vicky95 on October 10, 2012, 08:53:21 pm
So basically being ranked 1 in a strong cohort accounts for naught if the same student does not perform equally well in the exam.
Whereas a student who is ranked, say 10th in the cohort and does exceptionally well in the exam will now ace overall as his SAC GA score now gets automatically scaled up.
No this counts for a lot. The student will get the highest exam score as their SAC score. The 10th student will still do exceptionally well however his SAC GA depends on the 10th highest exam score.
Quote
Right, thanks so much for this detailed explanation. I think I've understood how the system works now.
Edit: Sorry no idea how to get my post out of that quote...lol
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: brenden on October 10, 2012, 08:57:34 pm
Hahaha, no worries at all Vicky's Owner. And FYI, you could have deleted the post and re-quoted :)
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Truck on October 11, 2012, 02:25:02 pm
So basically being ranked 1 in a strong cohort accounts for naught if the same student does not perform equally well in the exam.
Whereas a student who is ranked, say 10th in the cohort and does exceptionally well in the exam will now ace overall as his SAC GA score now gets automatically scaled up.
No this counts for a lot. The student will get the highest exam score as their SAC score. The 10th student will still do exceptionally well however his SAC GA depends on the 10th highest exam score.
Another quick question - I've been hearing how SAC scores get scaled up? So a student getting say 100/100 can't expect any scaling - go any higher than that? Is that his max SAC score?
Yep. The SAC scores are equivalent to exam scores. I've never seen someone get more than 100% on any VCAA exam.
And I'm not meaning to be prejudicial at all but I wouldn't worry about your ranking and SAC score etc etc going to MacRob.
Yeah that's true, to clarify my post, it won't matter for you nearly as much because you're at McRob.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Faith-PoweR on October 11, 2012, 03:28:48 pm
Can someone tell me how many marks do I need to get in the ESL exam for each section if I aim for 43+ How about the SAC? Thanks! :)
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: FlorianK on October 11, 2012, 06:36:03 pm
So basically being ranked 1 in a strong cohort accounts for naught if the same student does not perform equally well in the exam.
Whereas a student who is ranked, say 10th in the cohort and does exceptionally well in the exam will now ace overall as his SAC GA score now gets automatically scaled up.
No this counts for a lot. The student will get the highest exam score as their SAC score. The 10th student will still do exceptionally well however his SAC GA depends on the 10th highest exam score.
Another quick question - I've been hearing how SAC scores get scaled up? So a student getting say 100/100 can't expect any scaling - go any higher than that? Is that his max SAC score?
Yep. The SAC scores are equivalent to exam scores. I've never seen someone get more than 100% on any VCAA exam.
And I'm not meaning to be prejudicial at all but I wouldn't worry about your ranking and SAC score etc etc going to MacRob.
I think sacs scale lol. Basing off what my teacher showed me, some kid who was rank 2 in last year's cohort scored 28 and rank 7 scored 38?
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Holmes on November 08, 2012, 04:42:23 pm
So if there are three students, Thushan, Dan and Paul in a cohort and they each get an average SAC mark of 100, 70, 60 respectively, this means that Thushan will be ranked 1, Dan will be ranked 2 and Paul will be ranked 3. Say they all sit the exam, and on the exam day, Dan's beard has grown so much that he can't see his exam paper anymore, thus, their exam marks are 100, 20, 70.
This means that for the SAC GA - Thushan will get 100, Dan will get 70 and Paul will get 20.
So, who is this famous Thushan? A genius? :P
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: grannysmith on April 02, 2013, 07:27:12 pm
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: spectroscopy on April 09, 2013, 09:30:04 pm
i have a sac score question LOL if in a cohort of say 4, there are 3 students who are equal rank 1 and the other student is ranked last, come exam time the students scores are 100% 80% 70% and 60%, does that mean that the top 3 students would get 100% for their sacs, and the 4th student would get 60? because he would be the second highest rank but the 4th highest student? or would he get the 80% ? THANKS GUYS
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Neo on April 10, 2013, 07:45:58 pm
Hypothetical Question:
Let's say we have a cohort of students undertaking unit 3/4 'Methods' at some school. We have one hardworking student who performs significantly better than the rest of his cohort, who are, for the sake of this question, under performing (they are unwilling, lazy students)
All the SACs for the year have been completed and the cohort ranking sees the hardworking student well above the rest of his cohort. Soon enough the students sit the methods exam and score as follows:
The hardworking student's effort pays off, he receives full marks on both exams. The rest of the cohort, however, do not even attempt the questions and consequently they all get 0 for both exams.
Will the student's SAC mark (one of three graded assessments) be in any way affected by the performance of his cohort or will the student simply receive his own average exam mark as his score for the SAC component of the graded assessments?
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Lasercookie on April 10, 2013, 08:10:15 pm
The student won't be affected, since they would have been rank 1. His sac mark would be correlated with the highest exam mark from the cohort, which would have been his own.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Neo on April 10, 2013, 09:17:57 pm
The student won't be affected, since they would have been rank 1. His sac mark would be correlated with the highest exam mark from the cohort, which would have been his own.
Thank you for answering. So does this SAC score become his/her concrete GA mark or is this score further scaled by other factors (like the GAT for example)?
If there are other factors in regards to the scaling of the SAC mark, could someone care to identify them as well as the extent to which they affect the mark
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Lasercookie on April 12, 2013, 12:30:03 am
Thank you for answering. So does this SAC score become his/her concrete GA mark or is this score further scaled by other factors (like the GAT for example)?
If there are other factors in regards to the scaling of the SAC mark, could someone care to identify them as well as the extent to which they affect the mark
They always state stuff along the lines of that "In all such cases, the examination scores will always be the major influence."
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Professor Polonsky on April 12, 2013, 01:19:42 am
From those pages, it seems that the actual raw (unmoderated) SAC mark does matter, especially between quartiles.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: FlorianK on April 13, 2013, 12:53:43 am
btw the system for the SAC scaling takes into account people that do excepionally good or bad. For Example: For Chemistry I was ranked last or maybe second last in a group of 10 of which the best got an A in Exam 1 and a B+ in Exam 2. The rest of the class got C+ or lower for both. I got a B+ for Exam1 and an A for Exam 2 and my SACs scaled up to a B+.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Mao on May 01, 2013, 01:51:50 am
SAC GAs are often where most students get lost - and it is probably because most are not familiar with it.
First of all, what is important here is your overall SAC rank. This means that if you are ranked first, it doesn't matter if you are ranked first by a big margin or by a small margin. If you are ranked first, you are ranked first.
So now, say you are ranked nth. What VCAA will do is they will give you the nth exam mark in your cohort as your SAC mark.
So if there are three students, Thushan, Dan and Paul in a cohort and they each get an average SAC mark of 100, 70, 60 respectively, this means that Thushan will be ranked 1, Dan will be ranked 2 and Paul will be ranked 3. Say they all sit the exam, and on the exam day, Dan's beard has grown so much that he can't see his exam paper anymore, thus, their exam marks are 100, 20, 70.
This means that for the SAC GA - Thushan will get 100, Dan will get 70 and Paul will get 20.
I am almost certain this is not the case. This is an over-simplification of the statistical moderation process.
Here, they briefly outlined the method: - The statistical distribution (measured by quartiles) for SACs and exams are calculated - A scaling argument is used to align SACs quartiles and exams quartiles - Students' internal SAC scores are moderated (presumably via linear interpolation) to the exam distribution.
Crucially: - The relative rank is important only in the sense of finding the quartile ranges - The unmoderated SAC rank is important for the actual statistical moderation - Quartile populations are essentially moderated independently of each other. E.g. a student is only in competition with his/her quartile
To get the most benefit out of statistical moderation (i.e. for teachers to cheat the system): - the top 25% of cohort should have scores in a tight group near the top of the distribution, while the last person of the first quartile should have a much lower SAC score. This skews the distribution of scores within the top quartile towards the maximum, while increasing the interquartile range. - have at least 1 person of the cohort to achieve a near-perfect exam mark - students in the top quartile who don't have glorious exam marks would now receive glorious SAC marks
TL;DR, OP's comments on statistical moderation of SACs is a misinterpretation.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: brenden on May 01, 2013, 03:05:07 am
Here, they briefly outlined the method: - The statistical distribution (measured by quartiles) for SACs and exams are calculated - A scaling argument is used to align SACs quartiles and exams quartiles - Students' internal SAC scores are moderated (presumably via linear interpolation) to the exam distribution.
Crucially: - The relative rank is important only in the sense of finding the quartile ranges - The unmoderated SAC rank is important for the actual statistical moderation - Quartile populations are essentially moderated independently of each other. E.g. a student is only in competition with his/her quartile
To get the most benefit out of statistical moderation (i.e. for teachers to cheat the system): - the top 25% of cohort should have scores in a tight group near the top of the distribution, while the last person of the first quartile should have a much lower SAC score. This skews the distribution of scores within the top quartile towards the maximum, while increasing the interquartile range. - have at least 1 person of the cohort to achieve a near-perfect exam mark - students in the top quartile who don't have glorious exam marks would now receive glorious SAC marks
TL;DR, OP's comments on statistical moderation of SACs is a misinterpretation.
Thank you for this.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Dayman on May 03, 2013, 05:28:52 pm
Here, they briefly outlined the method: - The statistical distribution (measured by quartiles) for SACs and exams are calculated - A scaling argument is used to align SACs quartiles and exams quartiles - Students' internal SAC scores are moderated (presumably via linear interpolation) to the exam distribution.
Crucially: - The relative rank is important only in the sense of finding the quartile ranges - The unmoderated SAC rank is important for the actual statistical moderation - Quartile populations are essentially moderated independently of each other. E.g. a student is only in competition with his/her quartile
To get the most benefit out of statistical moderation (i.e. for teachers to cheat the system): - the top 25% of cohort should have scores in a tight group near the top of the distribution, while the last person of the first quartile should have a much lower SAC score. This skews the distribution of scores within the top quartile towards the maximum, while increasing the interquartile range. - have at least 1 person of the cohort to achieve a near-perfect exam mark - students in the top quartile who don't have glorious exam marks would now receive glorious SAC marks
TL;DR, OP's comments on statistical moderation of SACs is a misinterpretation.
Honestly you need to voice your opinion louder because I think yours is the most accurate.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Professor Polonsky on May 03, 2013, 05:32:04 pm
- Students' internal SAC scores are moderated (presumably via linear interpolation) to the exam distribution.
I was actually told (by a fairly reputable source), strangely enough, that it's a quadratic function between quartiles. Take it with a pinch of salt, but yeah.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: chem-nerd on May 03, 2013, 07:21:43 pm
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: lala1911 on May 03, 2013, 09:15:27 pm
Good post Mao. I was so shocked when I saw this thread. It just doesn't seem fair that if rank 1 scored 95% average SACs and rank 2 scores 94%, and the highest exam marks are 84% and 72%, that the rank 2 student would suffer 12%. There must be some complex equation to make it fairer.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Dayman on May 03, 2013, 10:38:56 pm
I sort of got to that here as well. I was actually told (by a fairly reputable source), strangely enough, that it's a quadratic function between quartiles. Take it with a pinch of salt, but yeah.
Wait so in English please, I've only just delve into the world of quartiles so I don't understand what you said sorry.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Mao on May 04, 2013, 12:24:17 am
I was actually told (by a fairly reputable source), strangely enough, that it's a quadratic function between quartiles. Take it with a pinch of salt, but yeah.
That's very interesting. The problem with quadratic splines (interpolation) is that we must impose an arbitrary gradient at some part of the curve. Generally, we use cubic splines to avoid this (for reasons I won't explain here). I drew up a quick quadratic spline for a set of hypothetical but realistic interquartile ranges:
(http://i.imgur.com/FYATpLJ.png) The boundary condition I chose were the extremes, but it does highlight how arbitrary the choice of boundary conditions can be. The brown curve is roughly what we expect, but it is really insignificantly different to a linear interpolation. I don't see the motivation behind the choice of a quadratic spline over linear interpolation. I also wonder what 'arbitrary' boundary condition they use.
TL;DR, I think quadratic functions are a terrible choice for this situation.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: hannah2013 on October 03, 2013, 07:13:49 pm
im confused because i was ranked about 4th or 5th in my cohort last year yet got the 2nd highest exam mark in my cohort and 2nd highest study score
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: brenden on October 03, 2013, 07:31:33 pm
ATAR is a percentile score. A 90 ATAR means you performed higher than 90% of other students.
See why an ATAR of 100 does not work well?
Fair enough :)
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: NP97 on August 23, 2014, 04:11:11 pm
I am at a school which does really well in VCE but am doing quite averagely in my SAC's. Usually, our grades get scaled up a grade or so by VCAA. If I get a high A to low A+ on my exam, and my internal scores are around B, what kind of scores am I looking at in that range?
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: fareseru on September 14, 2014, 11:44:46 pm
I am at a school which does really well in VCE but am doing quite averagely in my SAC's. Usually, our grades get scaled up a grade or so by VCAA. If I get a high A to low A+ on my exam, and my internal scores are around B, what kind of scores am I looking at in that range?
I have a fairly similar question - after reading through various stuff for hours, I'm still a little confused :s Basically, if a student does reasonably well throughout the year in English (let's say 80/100, ranked 15th) but receives the highest mark for the exam (30/30), how is their SAC score moderated (as they were deemed an excellent student by the examiners)? Or is the system ultimately promoting doing well throughout the year and doing well on the exam instead of actually using the year to work hard and improve in order to do well on the exam?
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Shyam995 on November 02, 2014, 05:21:59 pm
Does that mean if you get an ATAR of 65, your aggregate is better than 65% of the state? If so, how come 65 is around the average? I've never quite understood why it's not 50 ???
Just taking an educated answer to your question, remember that the AVERAGE AGGREGATE and the 50 AGGREGATE are two different things.
Remember that the average of a certain set of numbers is simply the addition of all of those numbers divided by how many there are.
Assume a "miniature victoria" home to 10 students who just got their atars. There atars were 30, 40, 50, 60, 65, 70, 80, 90, 95 ,99.95
When you average out these numbers, the AVERAGE ATAR AGGREGATE comes out to 68.
This is due to the fact that the amount of higher atars counteracts (to a certain extent) the amount of lower atars, to a point where the atar exceeds fairly above 50.
remember that the 50 AGGREGATE is where your smack bang in the middle. The average is a totallly different thing.
I think thats a good explanantion....
Anyways hope this helps!
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Kindergarten on October 26, 2015, 05:21:00 pm
So if I was in the second quartile for my sacs does that mean I'm effectively screwed as far as SS goes regardless of my exam mark?
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Zahra.rajabi44 on June 26, 2017, 05:15:45 pm
So if i get a sac result around 60/62% is it possible for me to aim around 35 study score?
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: keltingmeith on June 26, 2017, 05:43:39 pm
So if i get a sac result around 60/62% is it possible for me to aim around 35 study score?
It depends on where in the cohort you sit, how rank 1 does in the exam, how much the SAC was worth, what subject it was for... Quite an involved process to figure it out. Most likely, it's still very possible, just keep doing your best.
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Ashjames on August 11, 2017, 04:46:52 pm
Hey - just a quick question.
My coordinator has been a coordinator at the school for over 20 years. Today he told me [because I was stressing about my rank] that if you get above 35 as a SS in any subject, then ranking will not affect you. [ or I think if it was above 40 in your exam]
Is this true?? [not that I don't trust him :P]
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Joseph41 on August 11, 2017, 05:59:21 pm
My coordinator has been a coordinator at the school for over 20 years. Today he told me [because I was stressing about my rank] that if you get above 35 as a SS in any subject, then ranking will not affect you. [ or I think if it was above 40 in your exam]
Is this true?? [not that I don't trust him :P]
I'm not really following what your coordinator is suggesting here; could you clarify? :)
Title: Re: Guide to how Study Scores and ATARs are calculated!
Post by: Ashjames on August 11, 2017, 06:20:34 pm
Okay, so say if you are rank 5 for a subject and you manage to get a 40 in your exam- it will not scale down in relation to your SAC marks- and basically your rank in your SAC's will not affect it. So even if the people ranked higher than you still get bad in exams, you will still get a 40.
So, lets say you are rank 5, and all ranks above you get bad, it will not affect you [i.e their horrible exam marks] you will still get that 40- even if your GA 1 was b+, GA2 was an A and your exam mark was an A+. I don;t know how to explain this really.
But in basic English, he told me not to worry out my ranking because if I got an a+ [say for example a 42 in a subject] I will still end up getting a 42 as my SS for that subject- it will not change depending on how the others above me in ranking performed?