VTAC, the Victorian body responsible for figuring out ATARs and the like, is, of course, a professional and widely respected organisation. VTAC is staffed by very well-qualified boffiny stats types, just quietly doing their boffiny stats thing, and they don’t make mistakes. Well, except for this. And this. And really, really this.
Anyway, a few months ago the Evil Mathologre alerted us to some new(ly discovered) weirdness courtesy of the always-perfect VTAC. Or, maybe it’s courtesy of ACTAC, which is the national umbrella group encompassing all of the State-TACs. It’s difficult to tell, since, much like QANTAS, it seems that ACTAC cannot be contacted, appearing to exist only as an abstract concept. Anyway anyway, to the weirdness.
One of the genuinely tricky tasks that VTAC/ACTAC is assigned each year is the conversion of subject scores for prerequisites from one state to another. Let’s imagine, for example, that we have a NSW student, Eddie Wow, who has completed HSC and then moved to Victoria. In Extension 2 Mathematics, Eddie received a 42; that is at the upper end of Band E3, which ranges from 35 to 44. Now Eddie wants to know whether that score is good enough for him to be accepted into advanced mathematics in first year uni in Victoria. Well, Monash requires a 35 in Specialist Mathematics for their advanced subject, and Melbourne Uni requires a 38 for their accelerated stream. So, the question is, how to convert Eddie’s 42 in HSC Extension 2 Mathematics into a nominal VCE Specialist score.
The answer is, of course, there is no answer. Any such conversion scheme will necessarily be clunky, with a very high element of guesswork and arbitrariness. But the problem won’t go away, and one must do what one can. Unless, it seems, you’re VTAC.
This is how VTAC/ACTAC converted NSW HSC to Vic VCE for 2021: What does this all mean for Eddie? Eddie scored in Band E3, which VTAC has declared “Meets [a] Victorian Prerequisite at a specified level of 32”. Since 32 is below 38 and 35, Eddie loses. Eddie loses, that is, unless the Mathologre or their equivalent employs some discretion to ignore this nonsense.
Even without considering New South Wales’ bands, there is something starkly nuts about VTAC’s broad brush scheme. From 32 to 41, and ditto 23 to 31, covers a massive range of achievement in Specialist Mathematics, and in any subject. Which isn’t a big problem if the scores in between are uncommonly prerequisites. Such scores in between are very commonly prerequisites.
Why do this? Why instruct everyone to use such an unusable table? We asked.
We emailed VTAC and very quickly we received back a long, friendly and detailed reply. Our VTAC correspondent alerted us to the existence of ACTAC, and they noted the narrow purpose of the VTAC conversion tables, for determining broad prerequisites. This was opposed to the ATAR, “designed to be a nationally equivalent fine-grained rank”. As such, for the purposes of the subject conversion tables,
“it is neither useful or necessary to perform equipercentile matching or a similar process on cross-state systems to establish a fine-grained conversion at the score level”.
On NSW and Victoria specifically, our correspondent noted the use bands in NSW for these prerequisites, while the “vast majority” of Victorian prerequisites are listed in bands of 5, from 15 to 35. And, somehow thus,
“As New South Wales uses HSC performance bands to assess prerequisite satisfaction for its own HSC students and for interstate students, it is entirely appropriate for VTAC to state the equivalence for Victorian universities using the NSW performance band levels”.
More generally, our VTAC correspondent assured us that these conversions were all professionally done, with the State TACs comprising “expert level technical groups comprising mathematicians, statisticians, academics and education experts”. Our correspondent concluded,
“In summary, the method used to convert Victorian course prerequisite score requirements to NSW HSC performance bands is not an error requiring correction, but a robust process used and refined for over 20 years, developed by mathematically-qualified expert groups in a national collaboration between educational administration bodies in every state and territory.”
All very convincing. Except that the unusable VTAC table remains unusable.
Ignoring, for the moment, VTAC and VTAC’s unusable table, what should be done with our friend Eddie? It is unclear, but a reasonable approach is suggested by a second table, provided by NSW’s UAC, which associates 2021 NSW bands with VCE scores: This second table suggests that HSC’s Band E3, from 35 to 44, corresponds best-guessingly to VCE scores in the range 28 to 37. Then, further linear guessing would convert Eddies’s 42 to a nominal Specialist score of 35. Enough for Monash, but not enough for Melbourne. Lots of guesswork, but pretty clearly a more sensible and more useful guess than VTAC’s “at least 32”.
Why does VTAC not do something like this? We asked.
It took a while to find the time, but a couple weeks ago we replied to VTAC. We noted Victoria’s increments of 5 made VTAC’s table typically useless. We also suggested (before we discovered the second table and perhaps somewhat inaccurately) that the lack of granularity in VTAC’s conversion was systemically lowballing NSW students. We also indicated how impressed we were to hear that the conversion tables were the product of mathematically qualified expert groups, and so on.
We have not heard back. Presumably VTAC are just too busy with their mathematical experting and robust processing. You know them boffins.