MAV’s Sense and Censor Ability

We’ve written about MAV’s censorship previously. It seems, unfortunately, that we may have another such incident to write about in the near future. We’ll see.

There is also a third incident that we’ve long planned to write about, but have never gotten around to. It is rather involved, and we won’t give the full story here, but one specific aspect is perhaps worth telling now.

In 2016, we accepted an invitation from the MAV to give a keynote address at their Annual Conference. We chose as our keynote title Same Sermon, New Jokes. We also submitted a “bio pic” – the graphic above – and an abstract. The abstract indicated our contempt for twenty or so organisations and facets of Australian mathematics education.

A couple months later, the Conference organisers emailed to indicate their objection to our abstract. One can argue the merits of and the propriety of this objection, and we will write generally on this at a later date, but one aspect of the objection was particularly notable. The email included the following:

“While we welcome all points of view, we do need to be respectful of the organisations we work with, and with whom we need to maintain good relations … We would like you to re visit the text … without the criticism of formal organisations.”

We pushed back against the criticism, and ended our reply with what we intended as a rhetorical question:

“You wrote that you (plural) welcome all points of view, which I was very reassured to read. Given that, which formal organisations do you consider to be above criticism?”

The email reply from the organisers included a response:

“In regards to the formal organisations with which the MAV has relations, you have stated some of them, e.g. ACARA, VCAA.”

No one at the MAV, including the then President, indicated to us any problem with this request or its clarification.

For now, we’ll leave it there.

WitCH 37: A Foolproof Argument

We’re amazed we didn’t know about this one, which was brought to our attention by commenter P.N.. It comes from the 2013 Specialist Mathematics Exam 2: The sole comment on this question in the Examination Report is:

“All students were awarded [the] mark for this question.”

Yep, the question is plain stuffed. We think, however, there is more here than the simple wrongness, which is why we’ve made it a WitCH rather than a PoSWW. Happy hunting.

UPDATE (11/05) Steve C’s comment below has inspired an addition:

Update (20/05/20)

The third greatest issue with the exam question is that it is wrong: none of the available answers is correct. The second greatest issue is that the wrongness is obvious: if z^3 lies in a sector then the natural guess is that z will lie in one of three equally spaced sectors of a third the width, so God knows why the alarm bells weren’t ringing. The greatest issue is that VCAA didn’t have the guts or the basic integrity to fess up: not a single word of responsibility or remorse. Assholes.

Those are the elephants stomping through the room but, as commenters as have noted, there is plenty more awfulness in this question:

  • “Letting” z = a + bi is sloppy, confusing and pointless;
  • The term “quadrant” is undefined;
  • The use of “principal” is unnecessary;
  • “argument” is better thought as the measure of an angle not the angle itself;
  • Given z is a single complex number, “the complete set of values for Arg(z)” will consist of a single number.
  • The grammar isn’t.

SACs of Shit

SACs may not be the greatest problem with VCE mathematics, but they’re right up there. SACs are torture for teachers and torture for students. They teach nothing. As assessment, they are unnecessary, unreliable and phenomenally inefficient. They are a license for VCAA’s unaswerable auditors applying Kafkaesque rules to act either as favour-givers or as little Hitlers, as the mood takes them. These problems are currently amplified to eleven by VCAA’s “We’ll give you some kind of guidance in, oh, a little while” plan for the plague year.

For all of the awfulness of the above, that’s not the worst of it. The worst is that the majority of SACs are monumentally stupid. Literally. A SAC has the imposing presence of a monument, its towering stupidity casting a shadow over everything.

How are SACs so bad? Many contain errors, often subtle although too often not, but, as irritating as that is, that is not the main problem. The main problem is that they are mathematical nonsense. Typically they will present the student with a ridiculous model of a contrived problem, which is then all redone in greater, brain-bludgeoning generality by throwing in a needless parameter in a randomly chosen location. All of this is undertaken, of course, in the nihilistic world of CAS. Finally, somewhere near the end, the poor beleaguered student, who by this stage just wants to escape with their life, will be required to “comment on the model”, to which the usual response is “It’s really nice, please let me go” and to which the only reasonable response is “It’s fucking insane”.

How do we know SACs are this bad? Because we see them. We see the commercial SACs, and the sample SACs, and the past SACs, and the current SACs. Are they all as bad as we suggest? No, of course not. Specialist SACs are typically nowhere near as bad as Methods SACs, and even many Methods SACs will fall short of truly idiotic torture, rising only to the level of being dumb and painful. Then there are the rare few SACs we see that are good, resulting in an exchange:

“This actually makes sense. Who’s your teacher?”

“Oh, it’s Mr. ….”

“Ah. Yes.”

So, yes, the quality and worth of SACs varies widely, but the average is squarely in the neighbourhood of monumental, tortuous stupidity. Which bring us to the “why”. Why are SACs in general so awful? There are two reasons.

The first and fundamental reason is the VCAA and their view of what they imagine is a curriculum. VCE mathematics subjects are so shallow and so lacking in a foundation of solid reason, that almost any attempt at depth and substance in a SAC is destined to be farce. The VCAA has replaced foundation and depth with CAS, which reaches peak awfulness in SACs. The VCAA promotes the fantasy that CAS magically transforms students into mathematical explorers, clever little Lewises and Clarks skilfully navigating the conceptual wilderness. The reality, of course, is much less Lewis and Clark than it is Burke and Wills. To top it off, SACs must follow guidelines that Terry Gilliam would be proud of, giving us Burke and Wills’ Bogus Brazilian Journey. Or, just Eraserhead. Something like that.

The second reason is the teachers. Sort of. Even if the subjects were coherent, even if they were unpoisoned by CAS and were unconstrained by vague and ridiculous conditions, even then writing a good SAC would be a very difficult and massively time-consuming task. Most teachers just don’t have the mathematical background, or the literary skill, to write a coherent, correct and mathematically rich SAC; many cannot even recognise one. And, that’s writing a good SAC for this imaginary good subject; writing a good SAC for these fundamentally flawed subjects with their ridiculous constraints is close to impossible, even for a strong teacher. And which teachers, particularly weaker teachers, have the time to compose such a good SAC? Why bother trying? And so, with the greatest common sense, most teachers do not. Most teachers stick to the audit-proof and meaningless formulaic SAC bullshit that the VCAA expects and effectively demands.

The VCAA’s SAC system is a crime against mathematical humanity.

UPDATE (15/5)

We received the following from a student acquaintance (who hadn’t read this post):

Hi Marty, given the upcoming math SACs approaching soon, the pressure is on to practice and practice. Attached below is last year’s Methods SAC1 (Unit 3/4) for [the student’s school]. I remember many talented friends of mine who were stumped, and didn’t do very well on this SAC. Personally, I thought this SAC was horrifying. In contrast to Specialist, (I actually quite enjoy Specialist!), Methods seems to be a huge prick because of frustrating, ambiguous SACs containing questions seemingly cooked from the pits of hell itself. Are these sort of SACs common across the state?

The student is, of course, correct. The SAC, which comes from a highly respected school, is a nightmare in all of the ways canvassed above. From start to end it is idiotic CAS-driven pseudo-modelling, complete with Magritte nonsense and a pointlessly prissy grading scheme. And, yes, the SAC contains an error.

Of course we won’t reveal the school, much less any teachers involved, which means that we are also unable to critique the SAC in detail. But that is one of the insidious aspects of the SAC system; an entirely proper concern for privacy means that SAC nonsense, although endemic, fails to be exposed to the public critique that is so very much needed.

Should Schools Now Be Opening?

Just for a change, we’re asking a non-rhetorical question. So, ignoring the fact that ScoMoFo is a thug, and ignoring the fact that “Dumbo” Dan Tehan is a thug, is it time for schools to reopen?

Our suspicion is that, at least in Victoria, the answer is “no”. We haven’t thought hard about it, however. So, while we (try to find time to) think some more, we’d be interested in what others have to say.

Very quickly, here are the arguments we see for opening schools in Victoria:

  • Federal health officials suggest schools are safe.
  • The NSW study (not yet peer-reviewed) suggests schools are safe.
  • Childminding.
  • Year 12 students are getting seriously dicked around.

Here are the arguments we see for keeping schools in Victoria closed:

  • ScoMoFo is an idiot.
  • Dumbo Dan makes ScoMoFo look smart.
  • Daniel Andrews and his Chief Medical Officer are not idiots.
  • No one has a real sense of what will happen when restrictions ease.
  • The kids (P-11) miss a term of school? Big deal.

Vanessa’s Appt Concerns

Today, the Australian government released COVIDSafe, the Government’s coronavirus tracking app, based on Singapore’s TraceTogether version. The release comes complete with the Government’s predictable reassuring and cajoling and guilt-tripping. Should Australians trust them and use the app? Really? For us, there is a very simple answer: when and only when Vanessa Teague gives the all clear.

Vanessa is an expert on cryptography and, as it happens, is an ex-student and a good friend. She is very smart and is as principled a person as we have ever met. Along with many of her colleagues, Vanessa has been critical of the Government’s needless (and entirely predictable) secrecy over COVIDSafe. She has written a series of blogposts about their underlying concerns, and in particular the Government’s failure to follow up on promises and release COVIDSafe’s source code. This is Vanessa’s current stance on using the app (as of 23/04):

“In its TraceTogether form, I would be happy to run it on the train but refuse to run it in my home or office. I need to see the details of Australia’s version before I decide.”  

And, if that’s what Vanessa suggests then that’s what we’ll do, right up until Vanessa and her colleagues suggest otherwise. We’ll regularly be checking on Vanessa’s blog and twitter account.


Postscript: We had planned on writing about Vanessa a month or so ago, when she made the news. That story is highly relevant, since it involves privacy concerns, government screw-up, an arrogant and inept minister, a limp lettuce watchdog, a thuggish department secretary being matey matey with a vice chancellor, and a spineless university. Yep, same old, same old. But, given the speed of the times, we’ll probably have to leave that story be.


UPDATE (27/4)

The Minister for Health has today made an undertaking to release the source code “within two weeks”. We’ll see. (The formal agency response on privacy (26/4) states that such release will be “subject to consultation with the Australian Signals Directorate’s Australian Cyber Security Centre”.)

Vanessa and her colleagues have a new blog post (27/4). The post has been written “on a best-effort basis using decompiled code from the app, without access to server-side code or technical documentation.” Their conclusion:

Like TraceTogether, there are still serious privacy problems if we consider the central authority to be an adversary. That authority, whether Amazon, the Australian government or whoever accesses the server, can

    • recognise all your encryptedIDs if they are heard on Bluetooth devices as you go,
    • recognise them on your phone if it acquires it, and
    • learn your contacts if you test positive.

UPDATE (01/05)

We’re not going to bother with the nasty guilt-tripping on the COVIDSafe app, including from numerous media nitwits who should know better. This from Bernard Keane suffices.

Vanessa now has a very good twitter thread on the seemingly contradictory safe/not-safe messages from IT folk.

UPDATE (11/5) Vanessa has a twitter thread (08/05) on ScoMoFo’s latest round of silly buggers.

UPDATE (13/5) This will come as a great surprise, but it turns out that Greg Hunt is a dishonest piece of shit.

UPDATE (15/5) Vanessa and her colleagues have a new blog post (14/5): The missing server code, and why it matters.

UPDATE (20/5) Vanessa and her colleague Chris Culnane have a new blog post (19/5), on flaws in and corrections to the UK covid app (and why this was possible). Vanessa also has an accompanying twitter thread.

WitCH 36: Sub Standard

This WitCH is a companion to our previous, MitPY post, and is a little different from most of our WitCHes. Typically in a WitCH the sin is unarguable, and it is only the egregiousness of the sin that is up for debate. In this case, however, there is room for disagreement, along with some blatant sinning. It comes, predictably, from Cambridge’s Specialist Mathematics 3 & 4 (2020).

MitPY 6: Integration by Substitution

From frequent commenter, SRK:

A question for commenters: how to explain / teach integration by substitution? To organise discussion, consider the simple case

    \[\boldsymbol{ \int \frac{2x}{1+x^2}dx \,.}\]

Here are some options.

1) Let u = 1 + x^2. This gives \frac{du}{dx} = 2x, hence dx = \frac{du}{2x}. So our integral becomes \int \frac{2x}{u}\times \frac{du}{2x} = \int \frac{1}{u}du. Benefits: the abuse of notation here helps students get their integral in the correct form. Worry: I am uncomfortable with this because students generally just look at this and think “ok, so dy/dx is a fraction cancel top and bottom hey ho away we go”. I’m also unclear on whether, or the extent to which, I should penalise students for using this method in their work.

2)  Let u = 1 + x^2. This gives \frac{du}{dx} = 2x. So our integral becomes \int \frac{1}{u}\times \frac{du}{dx}dx = \int \frac{1}{u}du. Benefit. This last equality can be justified using chain rule. Worry: students find it more difficult to get their integral in the correct form.

3) \frac{2x}{1+x^2} has the form f'(g(x))g'(x) where g(x)=1+x^2 and f'(x) = \frac{1}{x}. Hence, the antiderivative is f(g(x)) = \log (1+x^2). This is just the antidifferentiation version of chain rule.  Benefit. I find this method crystal clear, and – at least conceptually – so do the students. Worry. Students often aren’t able to recognise the correct structure of the functions to make this work.

So I’m curious how other commenters approach this, what they’ve found has been effective / successful, and what other pros / cons there are with various methods.

UPDATE (21/04)

Following on from David’s comment below, and at the risk of splitting the discussion in two, we’ve posted a companion WitCH.