kitchen table math, the sequel

Wednesday, November 24, 2010

Christmas!

Aaaaw to Zzzzzd: The Words of Birds: North America, Britain, and Northern Europe

The First English Dictionary of Slang, 1699

The Classical Tradition

Six Books of Euclid

GPA Calculations

I was looking at the way my son's school calculates GPA and weighted GPA. Then I looked at how other schools calculate them. Since I was looking at high school web sites, I was only partially successful. In any case, many of them seem to be math-challenged. Even when I searched the web about how colleges calculate GPA (or not), I met with little success. We are told that colleges generally like to recalculate their own GPA. Why? If they have the numeric percentage grades, why do they have to sort them into GPA buckets (e.g. 83-87 is a 'B' = 3.0) and then come up with a new number that contains less information than the percentage grade. Perhaps some high schools send out only GPA bucket scores for each class, but do colleges know what the buckets are?

What I find more interesting are discussions that talk about how colleges like to use unweighted GPA scores. There is some sort of advantage to an 'A' in a regular course over a 'B' in an honors course. Maybe. I think it depends on whether you make it past an initial cut. Someone told me once that colleges use unweighted GPAs for the initial cut. That seems backwards to me. You want to use a weighted GPA (and rank and SAT and etc.) to make the initial cut, but then compare applicants based on unweighted GPA. Of course, they must first strip off all of the non-academic courses.

There is the Ivy League "Academic Index", which uses something called the "Converted Rank Score" (CRS) along with your SAT scores to come up with a number, that presumably, is used to determine whether you make it past a cutoff. The CRS number is based on your class rank and the size of the graduating class. Since most high schools rank based on a weighted GPA (including all fluff courses), this would indicate that class rank matters more than the unweighted GPA of core academic courses. That seems to be a poor game to play. If you are on the bubble, perhaps you might want to look at another college. I told my son that it might be nice to look at his GPA, but he should just try to get the best grades on his core academic courses. This came up because some kids at his high school are getting weird about GPA scores.

I do, however, tell him not to give away free points. For example, in science, they had a grade for whether they covered their books or not. I showed my son that if he didn't do it, his overall grade for the class would drop 3 points. I told him that it was like finding free money. Then there are the things you have no control over, like group grades. There was also the essay where he got an 80, but that was the second highest grade. Both of those things dropped his quarter grade by 5 points. There is not much you can do if a school has two different grading rules for the same course and you stuck with the wrong teacher. Things might average out in the end, but it's difficult while the student is going through it.

Monday, November 22, 2010

on beyond zebra

A friend sent me a link to this story last night:

"Infinite" is not a word you expect to find in a report on municipal spending. It's more of a science fiction–type term — Tremble, Earthling, before the infinite might of Galaxor! But there it was, in a recent report on San Francisco's finances: Spending on the city's employee retirement system in the past decade had grown at an "infinite" rate.

Naturally, that's an exaggeration. If you do the math, the city's retirement costs for employees in the past 10 years actually grew only 66,733 percent.

Still, you might call that a Galaxor-sized number.

In fiscal year 1999-2000, the city spent about $300,000 on its retirement system. In fiscal year 2009-10, it was $200.5 million. Benefits alone — not salaries, just benefits — for current and retired employees this year are budgeted at $993 million. Spending on retirees' health care and pensions is conservatively projected to triple within five years.

And after that? Infinite.

Let It Bleed
By Joe Eskenazi and Benjamin Wachs
Wednesday, Oct 20 2010
San Francisco Weekly News
I actually didn't even know there was such a thing as an infinite rate.

Sunday, November 21, 2010

Warren Buffet on insuring local and state bonds...

Some quotes from this letter sent out in 2008 are rather intriguing. All of this is addressed to the stockholder's view of course, who has a different interest from the local communities that decide to insure their bonds. But it seems that Warren Buffet has some insights into the finances of many public budgets...

"Early in 2008, we activated Berkshire Hathaway Assurance Company (“BHAC”) as an insurer of the tax-exempt bonds issued by states, cities and other local entities....BHAC has become not only the insurer of preference, but in many cases the sole insurer acceptable to bondholders. Nevertheless, we remain very cautious about the business we write and regard it as far from a sure thing that this insurance will ultimately be profitable for us...


The rationale behind very low premium rates for insuring tax-exempts has been that defaults have historically been few. But that record largely reflects the experience of entities that issued uninsured bonds. Insurance of tax-exempt bonds didn’t exist before 1971, and even after that most bonds remained uninsured.

A universe of tax-exempts fully covered by insurance would be certain to have a somewhat different loss experience from a group of uninsured, but otherwise similar bonds, the only question being how different. To understand why, let’s go back to 1975 when New York City was on the edge of bankruptcy. At the time its bonds – virtually all uninsured – were heavily held by the city’s wealthier residents as well as by New York banks and other institutions. These local bondholders deeply desired to solve the city’s fiscal problems. So before long, concessions and cooperation from a host of involved constituencies produced a solution. Without one, it was apparent to all that New York’s citizens and businesses would have experienced widespread and severe financial losses from their bond holdings.

Now, imagine that all of the city’s bonds had instead been insured by Berkshire. Would similar belt-tightening, tax increases, labor concessions, etc. have been forthcoming? Of course not. At a minimum, Berkshire would have been asked to “share” in the required sacrifices. And, considering our deep pockets, the required contribution would most certainly have been substantial.

Local governments are going to face far tougher fiscal problems in the future than they have to date. The pension liabilities I talked about in last year’s report will be a huge contributor to these woes. Many cities and states were surely horrified when they inspected the status of their funding at year-end 2008. The gap between assets and a realistic actuarial valuation of present liabilities is simply staggering.

When faced with large revenue shortfalls, communities that have all of their bonds insured will be more prone to develop “solutions” less favorable to bondholders than those communities that have uninsured bonds held by local banks and residents. "


Page 13 of Berkshire Hathaway's Letter to Stockholders


(p.s. don't ignore the first page.)

Saturday, November 20, 2010

money tree

Irvington School District's Financial Challenges

and: a new administrator at no extra cost to the district

from the SMO junior exam

(The competition is meant for 14 to 16 year olds.)

This was from the 2004 exam:
Find the number of digits in N where N is the product of all positive divisors of 100,000,000. (Note: For any positive integer A, we regard A itself as one of the divisors.)

Another one:
The number A=200420052006...2040 is formed when one puts the consecutive integers from 2004 to 2040 together. What is the remainder when A is divided by 9?


---

solution discussion for the first one:

Divisors come in pairs -- every divisor x, there must be a divisor n/x, and their product is n. (But if the divisor is a square root of n, then it is the same as the other divisor and it is only counted once.) How many pairs are there?

For n=10 there are two pairs (10-1 5-2), and we note the product is 10^2 = 100.
For n=100 there are five pairs (100-1, 25-4, 20-5, 10-10, 50-2) but one pair is degenerate and the product is 100^4 * 10 (=10^9).
For n=1000, there are eight pairs. Divisor product = 1000^8.
For n=10^8, the script I wrote in Mathematica tells me there are 81 divisors and the divisor product is 325.

The number of divisors for 10^n has an interesting trend, too. It seems to be (n+1)^2.

Friday, November 19, 2010

comments

I don't know what the heck has happened to the Comments sections or who ShirleyFenette2010 may or may not be.

What is a comment from whiteboydancefloor doing at kitchen table math?

déjà vu

Two parents discover Everyday Math:
As it turns out, our school district is using a controversial math curriculum called Everyday Mathematics, also known as "Reform Math." EM, as Everyday Mathematics is referred to by teachers, was developed by the University of Chicago, and according to their website, it is in use by about three million students nationwide. Here is one example of how simple addition "can" be performed using EM:


An example of what EM calls the "lattice method" for performing multiplication:


What becomes immediately clear is that several extra steps are now necessary to accomplish simple beeline computations. More steps will result in more errors -- only an idiot would claim otherwise. Eventually, EM students are taught four ways to add, five ways to subtract, four ways to multiply, and two ways to divide (traditional long division has been eschewed completely). Rote memorization is de-emphasized, and calculators (as well as estimating) are introduced in grade two.

Here is the basic rationale behind EM, directly from the University of Chicago website:
Research has shown that teaching the standard U.S. algorithms fails with large numbers of children, and that alternative algorithms are often easier for children to understand and learn. For this reason, Everyday Mathematics introduces children to a variety of alternative procedures in addition to the customary algorithms.

Links to or excerpts of said research are not provided -- we are to simply take these statements as fact. EM further claims to "make mathematics accessible to all students" by:

Incorporating individual, partner, and small group activities that make it possible for teachers to provide individualized feedback and assistance.

Encouraging risk-taking by establishing a learning environment that respects multiple problem solving strategies.

This couple is politically conservative, and as a result, the one thing they've got wrong is the idea that  liberal parents like this stuff when they don't. Not for the most part.

This passage took me aback:
What's worse, the methods purportedly being used to convince school boards to adopt EM reek suspiciously of Rules for Radicals: *
State that the traditional approach hasn't worked

Disparage testimony from those against the adoption as ideological and politically-motivated arguments

State that the success of any program depends on the teacher

Bring in teachers from affluent school districts as witnesses

Bring in a witness from a university
Never thought of these tactics in terms of Saul Alinsky.

Sheesh.


* Barry's article!

On top

The top earner in Westchester County and the region, Scarsdale's Michael V. McGill, earns $372,006 in total compensation.
Source: Demand for quality school superintendents fuels high salaries
Top-earner Scarsdale superintendent Michael V. McGill on our top students:
If you listen to people like Richard Elmore, who’s a teacher at Harvard, he says the very top top American kids are scoring about the 75th percentile on international studies. So we know our top performing kids are doing very well.
Source: A bully pulpit for the Superintendent of the Year | lohud blogs
Our very top students should be performing on par with Europe and Asia's very top students.

If they're not, then our very top superintendents are overpaid.

Superintendent salaries


Thursday, November 18, 2010

sitting in a class on the elementary classroom

unintentionally. I'm in the Curry School of Education library at UVA, working on a physics paper. (Wikipedia tells me the Curry School was apparently ranked #19 in the nation, #7 for secondary education in 2007 by the UNSWR.)

Now there are friends of mine who are Curry School students, and I've seen one tutor kids on Reformation history in Clemons library -- but they're going into secondary education. This elementary classroom situation is a little different. The entire thing is a simulation of a 3rd grade (math?!) classroom, with the instructor simulating the teacher and the ed students simulating...3rd grade students. The teacher to his credit, is engaging, and his rhetorical strategies seem useful.... just the activities they're doing don't seem all that intensive.

I really can't see how participating in a national healthy foods recipe competition is all that useful. (And I love food science.) I suppose it must be about the ingredients-measuring. And calendar-time planning.

Now there's another instructor (less charismatic) coming in to discuss how to teach young kids fractions; a new piece of software -- "designed for preschoolers but has been used in elementary schools sometimes up to 4th grade". I must say I like some aspects of what I see -- they give me a, "oh hey! that might be useful!" reaction. I'd keep the sound effects and the trusting kid narrative voice, but use really powerful, engaging diagrams.

I just see many ways in which their approach could be scaled so much up and made so much more intense. One thing I do see is an underestimation and a consistent underexpectation of the imaginations of children. A reminder of the kind of elementary school classroom I grew up in. (And my first grade teacher was a graduate of Harvard.) Certainly if they do mean to inspire children to discover concepts for themselves there isn't a lot of inspiration going on.

I currently do not see a lot of inspiration in the ed school students going on either, in a "imagine the possibilities!" sort of way.

Now the lecturer is showing how the software can be used, and how it can be used in Spanish -- but not showing them for example, how it might be customised or programmed to suit a lesson -- even when the lecturer was the leader of the team responsible for its development! (Though apparently other students did write the program.)

I don't know. I imagine that an elementary school teacher could be taught how to use Mathematica and write simple scripts (fun slider bars!) to create kid-friendly yet very engaging, powerful plots.

OK allows disabled students vouchers for private schools

Getting the vouchers, though is a "whole nuther ball of wax".

From Jay. P. Greene's blog post: Violators of OK’s Special Ed Voucher Law Get Good Mocking

Wednesday, November 17, 2010

TED, global health: does economic prosperity lead to good healthcare -- or is it the other way round?

The results may surprise you.

The other takeaway message of this is to take a critical look at things, and question assumptions. Averages can be deceiving when they mask distributions and what is really happening. You may be inclined for example, to think most of Sub-Saharan Africa have approximately the same issues with healthcare or economic development -- at least in the public mind they do.

I thought this would be relevant when discussing cost-effectiveness and development. Correlation does not imply causation, cause and effect and all that, etc.

Also the way he presents the data is really worth looking at. It's simply mind-expanding. Data presentation is far from making it look pretty -- it can tell you something new, that you might not have noticed.

The students here at UVA love TED talks -- from Commerce School students to biology majors to engineering students to Foreign Affairs students.


"teachers' unions, exposed"


These are interesting ads...

http://teachersunionexposed.com/ads.cfm

I am not against the principle of teachers' unions. (Are any of us?) Recently there does seem to be a movement among teachers who dissent against the current practices of their union and wish to nucleate around alternate paradigms...

Btw, I did NOT know that Michelle Rhee was forced to resign last month, after the incumbent mayor lost the elections. It never appeared in any news article I saw...


---

How is a 20-year-old student to assist in teacher union reform? It is not a particularly hot topic here on Grounds, in the face of healthcare reform, the DREAM Act (which students recently marched in support of) and the like. I am friends with several education majors and pre-TFA hopeful (I myself being one), and the Curry School is a major ed school here at UVA. Massive chalking? Printing random ads in black and white? I deplore stagnation so so much.

the spartan school and the low-income student

Far from an advocate of minimalism or the Lacedaemonian style of discipline, I am often struck by how schools elsewhere in the world can still retain excellent educations on so little a budget.

I admit, I have an ulterior agenda, one that pertains to immigration policy. I often hear the justification for stricter immigration controls (that is to repress even legal migrants) because additional migrants are overloading the resources of school systems. My answer is that a lot of districts have no idea how to manage low-income students or to construct low-cost schools.

Low-cost schools with excellent education, if you ask me, is a lot better than the alternative -- buildings that look like their high-income counterparts but the teaching does not. Schools in Singapore, ranging from the government-run "neighbourhood schools" to the independently-run distinguished names share some common design characteristics. They are not shamed by bare concrete floors; they are easy to spray-wash. I estimate that my primary school's (FMPS) current building cost at maximum $12 million SGD in todays' dollars, with a capacity of 1800 students. Contrast this with my high school district in Maine, which a few years ago wanted to take out a $57 million USD bond to renovate a high school that sees a student population between 900-1150 students. Where does the money go? I mean, Singapore, materials have to be imported from overseas; I imagine that cost of materials in New England is considerably cheaper. On top of this, FMPS managed to build several koi ponds and other feng-shui pleasing things in the courtyards -- a delight at every recess.

But the physical space is really a minute fraction of overall cost.

Is it the structure of the classes? From ages six to sixteen, schools do not try to imitate universities, though there are differentiated teachers even at primary one. So you don't have a single first-grade teacher trying to cover mother tongue languages, English, math and social/civics. But at the same time you're not shuffling kids from room to room in an imitation of the college environment. Yet I imagine a lot of American schools have this too. One thing my school did was to have morning and afternoon sessions -- from 7:50 am to 12:50 pm, and from 1:15 pm to 6:15 pm (with a 30-minute assembly before each session), so each classroom was effectively used by two different cohorts each day. Economization of space, I suppose.

How much expense is the food budget? Schools traditionally lease their canteen to eight vendors, which are in competition with each other, but the rent was cheap, such that the food prices were usually half that of the food prices found in the market across the road. But American schools can just as easily lease their premises to ARAMARK or some similar outsourcer, although a poor district may find itself paying for a large amount of free lunches.

Discipline perhaps. A large part of discipline was managed by peer leaders known as prefects -- but then again, it was needed, because a Singaporean teacher will typically manage a class of 40. Prefects were usually popular, respected students who could influence their peers, and were nominated for this reason. (I remember my form teacher once told the class monitor -- also a student discipline role -- she did not nominate him for prefect because he was "too quiet".) In my class, 11/41 students ended being prefects. (I was not the model student, and so, I was not one.) The system has its complaints; sometimes the prefects were not perfect instruments of administration and would sometimes conspire in mischief. But at the same time, perhaps the system takes considerable work out of classroom management, reducing stress and turnover. Does the system work well in Britain, who we inherited it from?

Books. The MOE much prefers thin textbooks and workbooks. Explanations in the textbooks are rather concise and visually illustrated (not with like, full-colour photographs, but with well-annotated diagrams). In primary school for each semester, my math textbook was at max a 100+ pages and was a low-cost paperback at $3.50 SGD. The workbook was a thin tome, costing like $2. And after exhausting the workbook, the teacher (with the assistance of the department) easily made up her own problems, or used past exams, and assessment books if need be. In secondary school the textbooks and workbooks were significantly thicker, but the prices were not ridiculous -- on the range of $10-$15 SGD usually.

Perhaps it's because publishers do not have a monopoly. Schoolbooks are meant to be worn; publishing in hardcover is ridiculous. I believe MOE drafts the material (with the help of participating teachers) and then has publishers bid to publish it the most cost-effectively. On the other hand, I have never heard of the Department of Education ever publishing anything besides reports, "standards" and "rubrics". I have never seen a Department of Education approval stamp on say, a textbook.


The money must be going somewhere. The Singapore administration would probably like the opportunity many districts in America are facing, with a large influx of migrant students. From a purely economic perspective, more students means more productive citizens in the future, and new opportunities to strengthen the state machinery, especially in the face of a declining birth rate. We don't have to be that cynical, but I really dislike how many local governments view their low-income students, treating them as liabilities rather than as future solutions to the poor neighbourhoods they came from.

Monday, November 15, 2010

do principals know who the best teachers are?

If principals and other administrators are doing their jobs, they already know who the best and worse teachers are. One year, Brookline administered one form of the Iowa Test of Basic Skills in the fall to third graders and the state administered a different form of the same test in the spring. I calculated the mean gain score for each teacher and asked the Assistant Superintendent for Curriculum and Instruction to tell me which teachers would have the highest and lowest gain scores. She got the group of highest teachers exactly right and missed only one of the lowest. I would expect building-based administrators to do even better. More formal analysis confirms my experience (Murnane, 1975; Jacob and Lefgren, 2008).

Measurement Matters: Perspectives on Education Policy from an Economist and School Board Member (pdf file)
by Kevin Lang

21st century skills

One of the goals of No Child Left Behind is to increase the availability of data. Part of the implicit model underlying No Child Left Behind is that with improved information, parents will recognize good and bad schools. Principals will identify good and bad teachers. District administrators will identify weak and strong principals, and state  administrators will recognize struggling school districts. Armed with this information, parents will choose with their feet, and the other actors will undertake the necessary reforms to improve education.

As an empirical economist I am, of course, sympathetic to the use of data, and as a school board member I pushed for more thorough evaluation of our programs. But the gap between the rhetoric and the ability to use education data effectively is large.

Few school districts have the resources to analyze statistical data in even remotely sophisticated ways. In the early days of the Massachusetts Comprehensive Assessment System (MCAS) tests, I visited the Assistant Superintendent for Curriculum and Instruction who was anxious to use the testing data to help Brookline address its achievement gap. The state Department of Education had provided each district with a CD with the complete results of each student’s MCAS test. In principle, it would be possible to pinpoint the exact questions on which the gap was greatest. The problem was that no one in the central administrative offices could figure out how to read the CD. I loaded the CD onto my laptop and quickly ascertained that the file could be read with Excel. Shortly thereafter, our Assistant Superintendent attended a meeting of her counterparts from the western (generally affluent) suburbs of Boston and discovered that Brookline was the only system that had succeeded in reading the CD. Districts have become somewhat more savvy about using data. A younger generation of administrators has more experience with computers, but relatively few would be able to link student report cards generated by the school district with SAT scores and the state tests.

Principals, district administrators, and even state-level administrators generally begin their careers as teachers, and relatively few teachers have strong backgrounds in statistical reasoning. In my experience, the people who rise to senior administrative positions in public education are smart. They understand in a general sense that estimates come with standard errors attached, but faced with a report that last year 43 percent and this year 56 percent of black students in fourth grade were profifi cient in math, few could tell you whether with 75 students each year, the change was statistically signifificant.

When I stepped down from the school board, one of my colleagues joked that they could all go back to treating correlation as causality. In education policy settings, one repeatedly hears statements like: “Students who take Algebra II in eighth grade meet the profifi ciency standard in grade ten. We must require all students to take Algebra II in eighth grade.” “Students taking math curriculum A and curriculum B get similar math SAT scores. The curricula are equally good.” “Students who are retained in grade continue to fall further behind. Retention is a bad policy.”2

School administrators may understand at some level that they are only looking at  correlations, but almost none have the training to address the issue of causality, and faced with a correlation, they will often interpret it causally in the absence of evidence to the contrary. The capacity to address causality, weaknesses of various measures, and other strengths and weaknesses of statistics is very limited. The Public Schools of Brookline recently recruited for a Director of Data Management and Evaluation. Although school board members generally are not (and should not be) involved in personnel decisions other than those involving the Superintendent, in this specific case the Superintendent asked me to participate in the candidate interviews. Many of the candidates held or had held similar positions in other districts. I asked each candidate how we could decide whether a math curriculum used by some, but not all, of our students was effective. Many of the candidates did not think of this question in statistical terms at all. Only one addressed the issue of selection—and we hired him.

Measurement Matters: Perspectives on Education Policy from an Economist and School Board Member (pdf file)
by Kevin Lang

Apparently they don't cover Excel in ed school.

Journal of Economic Perspectives

back issues are free online
The Journal of Economic Perspectives (JEP) attempts to fill a gap between the general interest press and most other academic economics journals. The journal aims to publish articles that will serve several goals: to synthesize and integrate lessons learned from active lines of economic research; to provide economic analysis of public policy issues; to encourage cross-fertilization of ideas among the fields of thinking; to offer readers an accessible source for state-of-the-art economic thinking; to suggest directions for future research; to provide insights and readings for classroom use; and to address issues relating to the economics profession. Articles appearing in the journal are normally solicited by the editors and associate editors. Proposals for topics and authors should be directed to the journal office.

Online issues of the Journal of Economic Perspectives published since 1999 are now publicly accessible at no charge, compliments of the American Economic Association.

Goody.

Friday, November 12, 2010

The Scribner Arithmetic

I was just talking to a woman here who is working on a transparency project (I'm in!). She got her start in all this when her district adopted TERC and rejected all forms of acceleration for gifted kids; now she's asking local townships for budget docs and the like.

Never occurred to me that the math wars can also have consequences for local government.

heh

She mentioned that when she looked back at her old textbooks, as well as her father's books, she was impressed. Her dad used Scribner Arithmetic in the 1950s.

Does anyone know anything about it?

The Scribner Arithmetic: Book 5

The Scribner Arithmetic: Book 5

I wish I could remember the math books my school bought when I was in 2nd grade, I think. I remember thinking they were beautiful. Not just beautiful but elegant, though I don't think I knew to apply that word to a book at the time.

Thursday, November 11, 2010

accent

I love this!

Only problem: I can't figure out which accent is my accent.

I think I just heard Cassy T, so apparently I'm clicking on flags too far north...