kitchen table math, the sequel: 10/26/14 - 11/2/14

Wednesday, October 29, 2014

Stop making sense

From Andrew Cuomo's campaign ad:
I want to invest $2 billion dollars to build the new technology classrooms of tomorrow. And I still believe the best education equipment is the kitchen table, and the best teacher is the parent.
-Andrew Cuomo
Needless to say, I will be voting 'No' on Proposition 3.

Tuesday, October 28, 2014

CDC writing lesson & expert raters using holistic rubrics

I've been meaning to correct the flu-shot post & am doing so now because Linda Seebach has given me a nudge.

When the CDC writes:
"Over a period of 30 years, between 1976 and 2006, estimates of flu-associated deaths in the United States range from a low of about 3,000 to a high of about 49,000 people."
...What they mean is:
Over a period of 30 years, between 1976 and 2006, estimates of annual flu-associated deaths in the United States range from a low of about 3,000 to a high of about 49,000 people.
It's funny. I think of writing as 'fuzzy' compared to math, but lately I've realized there's a precision to writing, too.

The first sentence means 3,000 over 30 years.

The second sentence, the one the CDC should have written, means 3,000 per year, in some but not all years.

I still question universal flu shots (although I certainly don't object to people getting flu shots if they like), especially given the fact that flu shots aren't particularly effective. Flu vaccine isn't like measles or mumps vaccine; the composition of each year's shot is an informed guess as to which viruses will be making the rounds this year.

As I think I mentioned in the earlier post, I recall a time when health authorities recommended flu shots only for vulnerable populations, not for the entire country. Vulnerable populations included the elderly (for whom vaccine isn't as effective), small children, and, I think, people with respiratory ailments (hence: flu-associated deaths).

Reading between the lines on the CDC page, I wonder whether the universal flu-shot campaign is intended to reduce exposure of vulnerable populations to the flu by reducing the incidence of influenza in non-vulnerable populations.

The elderly don't respond particularly well to flu vaccine.

Their best protection comes from other people not getting the flu, and thus not exposing them.

Thinking about flu shots, I'm reminded of my friend in LA who refused to get flu shots because the only time she ever lost any weight was when she got the flu.

Speaking of precision

Speaking of precision, I'm reading a fascinating study of college writing quality as defined by "expert raters ... using a holistic rubric."

(And, yes, that construction does give me pause. Expert raters using a holistic rubric are the people who decided that my SAT essay on freedom and macroeconomics was worse than my son's SAT essay citing Martin Luther King.)

A major finding: good writing, to an expert rater using a holistic rubric, isn't any more cohesive than bad writing.

Cohesion, pretty much the sine qua non of good writing outside of college, has no bearing one way or another on an expert rater.

Instead, what matters are:
  1. Using lots of words before getting to the main verb (more is better)
  2. Using lots of different words
  3. Using low-frequency words (aka big words
If you've spent any time in academia, you already know this, and it's been a conundrum for me, speaking as an instructor of freshman composition.

Good writing as defined by composition textbooks and style guides isn't good writing as defined by the people grading papers.

Monday, October 27, 2014


Digitopoly on the TI-84

I share his pain.

Does the 21st century have a shortage of software amateurs?

I have absolutely no way of evaluating whether the following is good or bad advice:
“Software developers” is one of the job categories expected to grow the most over the next decade.

But in addition to many thousands of software professionals, we need far more software amateurs. McKinsey & Co. argued a few years ago that we need more than 1.5 million “data-savvy managers” in the U.S. alone if we’re going to succeed with big data, and it’s hard to be data-savvy without understanding how software works.

Even if you’ve left school, it’s not too late. There are many resources available to help you learn how to code at a basic level. The language doesn’t matter.

Learn to code, and learn to live in the 21st century.

Tom Davenport (@tdav) is a Distinguished Professor at Babson College, a research fellow at the Center for Digital Business, director of research at the International Institute for Analytics, and a senior adviser to Deloitte Analytics.

Why All Employees Must Learn to Code | WSJ

Sunday, October 26, 2014


I'm reading the new Ebola book, David Quammen's Ebola: The Natural and Human History of a Deadly Virus, excerpted from his 2012 book Spillover.

Spillover is the Quammen's term for diseases spilling over from non-human animals to us.

Yesterday I realized that "spillover" isn't a bad term for what seems to be happening to tennis instruction: constructivism and learning-by-doing are spilling over to tennis.

At least, that's the way it looks to me. I hope I'm wrong.

I've re-upped my tennis lessons, on grounds that I need a hobby. This go-round, I've enrolled in a tennis clinic, something I'd never done before.

I've been to three clinics so far, and I'm not seeing much direct instruction.

In the first clinic, the instructor told me "not to think" and to "use your instincts."

I don't have any instincts where tennis is concerned, and the instincts I do have are wrong.

e.g.: When you hit the ball, you're supposed to keep looking at the spot where the ball was instead of following its trajectory back across the net. Looking at the spot where a tennis ball used to be is completely unnatural; every fiber of my being tells me Don't do what Roger Federer does.

Moreover, I find it extremely difficult even to know whether I've kept my head down or not. I need an instructor to tell me.

The clinic went badly enough that I actually walked out of the 2nd class (!), after becoming embroiled in an unwinnable argument with the instructor on the question of my attitude.

The class had been practicing hitting the ball back and forth across the net--no scoring--and I had opted to hit a ball on the second bounce.

I hit the ball on the second bounce because my private instructor usually had me hit second bounces if I could, and because the clinic instructor was himself hitting balls that were out of bounds.

So I thought the rule was: in bounds or out, hit the ball if you can.

But no.

The instructor, who had opened the class by telling me I "didn't belong" but I could stay for the day, told me I had erred, then said primly: "In tennis, when the ball bounces twice, it's out of play."

I said: "I know that."

He said I had no reason to take my frustration out on him.

I said "You were hitting balls that are out, I thought we were supposed to hit balls that are out if we can."

He said, again, that I was frustrated and I should not take my frustration out on him.

Naturally I denied having done any such thing; he said I had but I "didn't know it"; I said I hadn't; he said I had ---- the whole scene was ludicrous.

We were now swatting Did/Did not back and forth across our own invisible net, and the exchange was turning into a very long rally indeed, leaving the other two ladies in the class standing clueless on the opposite baseline, undoubtedly wondering what was going on and when we were going to start having a class again.

At one point I tried to end the quarrel by telling the instructor, who was young enough to be my son and then some, that in life, when you say something that has obviously ticked off another person  (especially another person old enough to be your mother), you take it back. 

That's how you get along with people. 

He swatted that one right back at me, saying, yet again, that I was frustrated, and I was directing my frustration at him.

He wasn't going to give an inch, and I certainly wasn't going to give an inch, seeing as how I'm twice the instructor's age and I'm the customer to boot.

So I left, with the instructor still calling after me "You have no reason to act like this."


Back to 'spillover,' the instructor's approach to teaching tennis had a fair amount to do with the fact that our dissing war erupted in the first place.

His approach was simply to run drills: advanced drills only one student in the class was remotely equipped to do. Forehand, backhand, volley, lob. Very difficult. We were starting at the top, beginning with the 'whole,' not the component parts, and with predictable results. Nobody could maintain any form to speak of, and there were multiple mis-hits and outright whiffs.

After the drills (this was a beginner's class, by the way), we "practiced" serving, also with zero instruction. My classmates were dinking the ball across the net, and so was I.

Then we played doubles tennis for points and we were supposed to have strategy.

We were learning tennis by playing tennis.

Except nobody was learning.


My third clinic, with a different teacher, was a much happier experience, and the instructor gave plenty of direct instruction. She was also responsive; as soon as she saw that I wanted  intervention and instruction, she provided it.

But still, she wasn't breaking things down.

In her class, too, we were doing the same advanced drills none of us could do .... and then, when we played a game, the instructor told us 10 Things About Doubles Strategy we were supposed to remember and use.

There's no way a beginner can remember 10 Things About Doubles Strategy, not while also attempting actually to do those 10 Things and get the ball back across the net.

More learning tennis by playing tennis.


I'm told that tennis instruction used to be different. Tennis teachers worked on form & watched as their students practiced technique over and over until they had it down.

That approach seems to be fading, and I blame spillover from our public schools.

People teaching tennis or continuing education classes are teaching the way K-12 teachers teach writing and math and grammar. Via discovery.

Their experience of schooling didn't instill within them a gut understanding that memory is limited, that subjects and skills must be broken down into bite-size pieces a student can remember long enough to practice and master.

So they run drills and have students play pretend doubles.


Now Ed is giving me lessons --- we are becoming an afterschooling family for tennis.

And I'll take more private lessons, the grown-up equivalent of hiring a tutor.

Talk about spillover.

Lockhart's lament redux

"The essence of mathematics is recognizing interesting patterns in interesting abstractions of reality and finding properties of those patterns and abstractions."

Everything About The Way We Teach Math Is Wrong
This strikes me as completely wrong, not that I have much confidence in my intuitions concerning the essence of math. So take this as a confession, not an argument.

"Recognizing interesting patterns" -- even "recognizing interesting patterns in interesting abstractions of reality" -- strikes me as the toolkit approach to math.

I personally -- another confession, not an argument -- can't stand the toolkit approach to math. Blech!

I have no interest -- none! -- in endless iterations of function problems designed to determine how much profit the guitar teacher will make teaching x number of students while paying y rent on the studio for 20 weeks, or whether Jim should buy the monthly contract or the annual, as useful and important as those questions are in daily living.

Nor do I relish the thought of encountering yet another roller coaster depicted as yet another instance of geometry, or another textbook with a nautilus shell splashed across the cover. Enough with the nautili.

If you want to make me hate math, real-world math will do the job.

That reminds me.

I did not, as a child, solve two trains leaving the station problems, and I wish I had. I was utterly charmed by the two-trains problems when I encountered them as an adult, working my way through "Russian Math."*

I don't remember whether we were asked to solve bathtub problems (I think we were), and I was charmed by those problems, too.

(Speaking of the real world, the bathtub problem is all you need to know to understand why fiscal stimulus doesn't work when the Federal Reserve targets inflation. One party is putting money into the system; the other party is taking it back out.)

To be fair, I'm not at all sure that "toolkit math" is what Lockhart actually means: "That’s what math is — wondering, playing, amusing yourself with your imagination."

Nevertheless, inside K-12, the toolkit approach is what look-for-patterns turns into.

Look for patterns may be a bit out of date.

Today, with Common Core, at least here in NY, we've moved beyond look-for-patterns to modeling, for pete's sake. In my district, the entire high school mathematics curriculum, the entire rationale for the entire mathematics curriculum, is modeling.

Lots and lots of function problems modeling stuff nobody cares about.

This is always the conundrum with constructivism and progressive education.

Progressive educators think the real world is fun and motivating.

* Mathematics 6 by Enn Nurk and Aksel Telgmaa