Misconceptions about science

Not long ago (29 April) an article titled “AAAS Testing Web Site Probes Students’ Misconceptions About Science” appeared in Science. The website is assessment.aaas.org (free registration required). Science matter

It includes this graphic, with the caption, “The answer is D. Nearly 70% of students tested by Project 2061 answered correctly, but 17% chose answer A. By offering insight on students’ misconceptions, the new assessments Web site can help shape more effective teaching.”

Do you find this question as annoying as I do? I take D to say that all matter is atoms, which is plainly not the case.

The test-wise student will realize that it’s the answer they’re going for, of course, though a case can be made for A (read it like this: “Atoms are not [identical with] matter, but they are contained in [the the set of all] matter”).

How much math do we really need?

G.V. Ramanathan, professor emeritus of mathematics, statistics and computer science at the University of Illinois at Chicago:

How much math do we really need?

… How much math do you really need in everyday life? Ask yourself that — and also the next 10 people you meet, say, your plumber, your lawyer, your grocer, your mechanic, your physician or even a math teacher.

Unlike literature, history, politics and music, math has little relevance to everyday life. That courses such as “Quantitative Reasoning” improve critical thinking is an unsubstantiated myth. All the mathematics one needs in real life can be learned in early years without much fuss. Most adults have no contact with math at work, nor do they curl up with an algebra book for relaxation. …

Five long years (and class-size reduction)

I note, somewhat belatedly, that I’ve been blogging here since January 2005 (or November 2004, if you want to count a first experimental WordPress post).

My first substantive post, BBC: Small-class pupils ‘do no better’, began:

New British research suggests that there “is no evidence that children in smaller primary classes do better in maths or English”.

Anniversaries aside, I bring up that post because it’s still a live subject. In December, a local editor opined (emphasis mine),

School officials are considering “eliminating class size reductions” in kindergarten through third grade. That means that instead of one teacher for every 20 students there may be half again as many students crowded into the classroom. Superintendent Rob Gaskill says there may soon be as many as 32 young scholars in a classroom. There is universal agreement that such a change would have profound implications for the education of young students.

…and our local school board, pushing for a local parcel tax, ranked class-size reduction near the bottom of a list of potential cost-cutting measures.

Class-size reduction (CSR) is popular in California, especially with parents and teachers, but there’s no good evidence that it leads to better educational outcomes, at least not the way it’s implemented here. CSR in California typically means reducing K–3 classes from about 30 to 20 students. What sketchy evidence that exists for CSR benefits is limited to class sizes in the 12–15 range. That, and unsupported claims that it “stands to reason” that CSR is beneficial.

CSR is expensive, and needs better justification than we’ve seen to date.

Teach to the back of the envelope

(I have a draft post on “teaching to the test” rattling around somewhere, hence the title of this one.)

RCA AirnergyThe gadget shown here was displayed at the recent Consumer Electronics Show. Cnet reported:

The device, called the Airnergy, uses an antenna and circuitry to harvest the energy and an internal battery to store the electrical charge. A company representative told OhGizmo that they were able to charge a BlackBerry from 30 percent to full charge in about 90 minutes using the ambient Wi-Fi signal at CES, although the charge time varies depending on how close the battery is to the original signal.

Now, this doesn’t really pass the sniff test, but, after all, it’s RCA, and they “demonstrated” it, so what the hell? The point of this post is that a judgement like this can be informed by a little back-of-the-envelope calculating, and that this is an example of the kind of skill that I’ll argue elsewhere, eventually, ought to be possessed by any graduate of a high school physics class.

We need some basic facts first. Wikipedia tells us that wifi base stations are limited by the FCC to 4 watts output. My cellphone battery is labeled: 3.7VDC 1150mAH. Assuming 100% charging efficiency, that’s 4.255 watt-hours required for a full charge. I’ll guess from the picture that the receiving antenna is 100 cm2 and that we put it a meter from the transmitter. How much power does the charger “see”?

We know (or can easily look up) that the surface of sphere is 4πr2, so the surface of a sphere with a radius of a meter is about 12m2, or 120,000cm2. Our 100cm2 antenna represents 100/120,000 or 1/1200 of the sphere, which is 4mW.

So at a distance of a meter, we’re looking at 1000 hours to fully charge my Palm Centro battery.

Notice that we’ve erred on the side of generosity to the RCA device. Neither the antenna nor the charger nor the battery charging system is going to be 100% efficient, and the device itself looks to be smaller than 10x10cm. And we’re not going to be within a meter of the wifi box at our local Starbucks.

It’s apparent that, to the extent that the device actually works, it does so only by being in very close proximity to the wifi transmitter.

Now, I suppose there’s a test question here that we could (and should) teach to. Quote the Cnet article and ask, “Is this device practical? Justify your conclusion.” Trouble is, that question requires the kind of answer that’s impossible to grade automatically, and in general, it seems to me that the same thing is true whenever we test practical skills—knowing how, rather than knowing that.

More Real Soon Now.

Addendum: If I were grading the answers to that question, here are some of the elements I’d be looking for.

  • We’re interested in how much power is available from the wifi transmitter, and how much energy (power times time) is required.
  • We’re interested in the area of the surface of a sphere, and the notion that the power available to the device drops with the square of the distance from the transmitter.
  • Assumptions ought to be conservative. If the answer claims that the device is practical, then it should make conservative assumptions about efficiency and size; if not, then (as above) the conservative assumptions go the other way, giving the device the benefit of the doubt.
  • If the answer concludes that the device is not practical, it would be a plus to suggest what RCA is up to, and how it might have been “demonstrated”.

Why aren’t children taught to touch-type at school?

Gordon Rayner in The Telegraph (strike-out mine):

For more than a century, the cornerstones of education have been reading, writing and arithmetic, but surely every British child would benefit if we added a fourth core skill to that list: touch-typing.

All children are given endless hours of coaching in how to use the most common computer applications, such as Windows, spreadsheets and PowerPoint, all of which are likely to have moved on significantly by the time current primary school pupils enter the world of work.

Yet they are taught how to use these programs without being taught the most basic computing skill of all – typing. It is the modern-day equivalent of teaching a child to do joined-up writing without ever showing them how to hold a pencil. …

Looking (way, way) back on my high-school career, I see now that the single most useful class I took, measured in day-to-day utility these decades later, was a half-semester of typing. I took the course because I ran out of other classes in my rural high school (there were 16 in my class that junior year) in an era in which there were typewriters, not computers, on the world’s desktops.

Public Deeply Ignorant About Cap and Trade

OK, this can hardly be surprising. But still…

Matthew Yglesias: Public Deeply Ignorant About Cap and Trade

Via Dave Weigel, an unusually useful poll from Rasmussen Reports:<

Given a choice of three options, just 24 percent of voters can correctly identify the cap-and-trade proposal as something that deals with environmental issues. A slightly higher number (29 percent) believe the proposal has something to do with regulating Wall Street while 17 percent think the term applies to health care reform. A plurality (30 percent) have no idea.

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The political press has a very strong structural bias toward overestimating the extent to which the public has real opinions about hot political issues. I wish more pollsters would put these kinds of polls in the field that do something to probe the extent of public ignorance. Polls that attempt to directly probe the public’s views about cap and trade wind up measuring a lot of pseudo-opinion. As you can see right in this result, people are incredibly unwilling to admit that they “don’t know” something or other. Thus 46 percent of the public says they know what cap and trade is about even though they don’t, in fact, know what it’s about.

Science literacy

This has been floating around for a while, and I’ve been meaning to mention it. So here goes.

Science Literacy — American Adults ‘Flunk’ Basic Science, Says Survey

  • Only 53% of adults know how long it takes for the Earth to revolve around the Sun.
  • Only 59% of adults know that the earliest humans and dinosaurs did not live at the same time.
  • Only 47% of adults can roughly approximate the percent of the Earth’s surface that is covered with water.
  • Only 21% of adults answered all three questions correctly.

We see these surveys from time to time, and I don’t know whether to be skeptical. I can see missing #3 (the correct answer is about 70%, and they accepted 65–75%), but #1 is hard to believe. Here’s the actual question with its choices:

Question #1
How long does it take for the Earth to go around the Sun?

  • One day
  • One week
  • One month
  • One year
  • Not sure

Half of all adults got this wrong? Really? We’re in deep, deep shit. One can only hope that it’s the same folks who don’t get around to voting.

Some obvious comments about school improvement and the achievement gap.

This is Harry Brighouse at Crooked Timber. My guess is that our local administrators would insist , mostly, that “that’s what we’re already doing”. Teachers maybe not quite so much. And yet…

Go read the whole thing, and don’t neglect the comments.

Some obvious comments about school improvement and the achievement gap.

… How are you going to raise achievement of anyone? In normal industries there are two ways to increase output. Either you increase productivity, or you increase the inputs (in the case of education this is mainly going to come in the form of additional labour). Are you being given extra resources with which to purchase more labour? My guess is that, in the current environment in the US at least, the answer to that is “no”. So, you have to somehow increase productivity, that is increase the effectiveness of the teachers you already have.

So, what increase in achievement are you aiming for? Do you really think that you are going to close the achievement gap? That is, do you really think that you are going to get the lowest achievers in your school achieving at a higher level than the highest achievers currently do? (which is what you have to do if you are going to pursue school improvement at the same time). Think for a moment at the Herculean increase in productivity that would require. Do you really think there is that much slack in the school? Or do you mean, by addressing the achievement gap, something much more modest, like increasing the achievement of the highest achievers by 5% and that of the lowest by 10%? If so, and if you are going to be improving the school, then you still need to find something between 5 and 10% increase in effectiveness.

How are you going to do this?

Nobody denies that schools have lots of inefficiencies in them (or rather, some deny this publicly, but none do privately when pushed—my experience is that when a teacher denies there is any waste in their district, the easiest way to get them to retract is to ask what they did during their last in-service). But some of those inefficiencies are not within your power to eliminate; you cannot fire the worst teachers and principals, for example, or prohibit teachers from attending wasteful district meetings. The constraints are less strict if your district is on board with improvement, and is willing to implement district-wide policies that make sense. But still, you have limited space. Other inefficiencies are just difficult to identify. Mainly, what you want to do is improve the quality of the classroom teaching, and improve the fit between students and teachers (e.g., if you find that some teachers work especially well with middle-level achievers you assign them to classes populated by such children; if you find some work very badly with high achievers you don’t assign them to such classes). …

The Worst Option, Except for All the Others

Ryan Avent.

The Worst Option, Except for All the Others

The issue is this — banks have assets that are worth much less than they’re currently being valued on the books. If banks fix this problem, they are suddenly and obviously insolvent. If they don’t, then they linger on in zombie mode, dragging down the broader economy, for years. The government therefore has to get rid of some of these assets. If it pays book value, then the taxpayers basically hand an extraordinary amount of money over to the banks. If it pays market value, the banks are insolvent. If the government pays something in the middle, then the taxpayers take a bath, and the banks are probably still insolvent.

A very bad solution to this crisis is nationalization. It’s bad because there are risks that the government will run the banks poorly, or make questionable loans, or that nationalization will be contagious — fear of nationalization will cause investors to abandon healthy banks, forcing the government to nationalize the entire banking sector instead of just the rotten firms. But as bad as nationalization is, it’s better than the other available solutions. No one wants to take this step, but given that taxpayers are going to be spending tons of money and taking on piles of risk to fix the banking sector, it makes sense that whatever value is left in the firms be confiscated to offset the costs (with the understanding that they’ll be re-privatized as soon as conditions allow).

Absent a definitive solution to this problem, banks will linger on in zombie mode, afraid or unable to facilitate economic activity appropriately. A definitive solution sans nationalization means an extremely expensive, and in all likelihood politically impossible, transfer of government money to the banks. It’s time to get over our fear of the word nationalization and do what’s best for the economy and for taxpayers.

Consider, for example, the extant worse-yet option, TARP. This is Michael R. Crittenden, Dow Jones Newswires, via CNN:

… “Our money — and our economy — are on the line, and we all have a stake in the outcome,” said Harvard Law School professor Elizabeth Warren in her prepared remarks for a Senate Banking Committee hearing.

Warren heads the five-member congressional oversight panel overseeing the TARP, and said that the group on Friday will issue a report suggesting Treasury has significantly overpaid for the assets it has purchased from financial institutions. She said an analysis of 10 of the TARP transactions, when extrapolated for all of the purchases made in 2008, suggests Treasury paid $254 billion for assets worth approximately $176 billion, a shortfall of $78 billion.

“Treasury paid substantially more for the assets it purchased under the TARP than their then-current market value,” Warren said. …

One more bit of Avent’s piece:

The plan, now, is to guarantee some assets and buy others at a price between book value (what the banks say an asset is worth) and actual value, using money from the second half of the TARP allotment, that is, something less than $350 billion. Which basically means that the adminstration seems content to perpetuate the old policy of doing something inadequate because something has to be done.

Dean Baker on IOUSA

Which I haven’t seen. Follow the review link for a readable lesson in political economics.

Response to IOUSA

In case you’ve missed the hype, IOUSA is a documentary making the case that the U.S. budget is hopelessly out of control and that our current spending patterns will bankrupt our children. The film features such noteworthy characters as Alan “Bubbles” Greenspan, Robert “Don’t Regulate Credit Default Swaps” Rubin, and former presidential candidate Ron Paul.

This film should be viewed as part of a larger effort to dismantle Social Security and Medicare, the country’s core safety net programs. The reality is that our budget is essentially fine, it is our health care system that is out of control. But fixing health care would require going after the drug companies, the insurance companies, and highly paid medical specialists. But those folks are all powerful, so the IOUSA crew went after old people instead.

You can get CEPR’s movie review here.

David Brooks is creepy

He’s not alone, I’m sure. In an opinion piece in the NY Times, Brooks informs us that US education is going to hell in a handbasket. We’re falling behind.

America’s edge boosted productivity and growth. But the happy era ended around 1970 when America’s educational progress slowed to a crawl. Between 1975 and 1990, educational attainments stagnated completely. Since then, progress has been modest. America’s lead over its economic rivals has been entirely forfeited, with many nations surging ahead in school attainment.

Well, OK. I’m skeptical of golden-age claims, but there’s no denying that we’ve made a hash of our schools. Maybe because states like California, once exemplary educators, have cut public education funding in half, as a fraction of personal income? No say Brooks’s sources.

It’s not falling school quality, [Heckman] argues. Nor is it primarily a shortage of funding or rising college tuition costs. Instead, Heckman directs attention at family environments, which have deteriorated over the past 40 years.

Heckman points out that big gaps in educational attainment are present at age 5. Some children are bathed in an atmosphere that promotes human capital development and, increasingly, more are not.

How does Heckman know? He “intuits” it, via “common sense”. Our children need to be “bathed in an atmosphere that promotes human capital development.”

Creepy.

NCLB close to home

I wrote a piece over at Coastsider.com on what is, in the event, a rather minor agenda item from the last meeting of our local school board.

The district’s middle school has reached the final stages of NCLB’s “Program Improvement” (that’s what California calls it; I think the Feds say “School Improvement”). Having failed to made “Adequate Yearly Progress” for six years running, the school was due for “major restructuring” of its governance. In California, that means creating Yet Another Committee, and business pretty much as usual.

That’s not all bad, but it’s a missed opportunity. Read the whole thing.

Thinking bigger about schools

Bob Herbert in the NY Times:

Our Schools Must Do Better

The latest federal test results showed some improvement in public school math and reading scores, but there is no reason to celebrate these minuscule gains. We need so much more. A four-year college degree is now all but mandatory for building and sustaining a middle-class standard of living in the U.S.

Over the next 20 or 30 years, when today’s children are raising children of their own in an ever more technologically advanced and globalized society, the educational requirements will only grow more rigorous and unforgiving.

A one- or two-point gain in fourth grade test scores here or there is not meaningful in the face of that overarching 21st-century challenge.

What’s needed is a wholesale transformation of the public school system….

“We’re not good at thinking about magnitudes,” said Thomas Kane, a professor of education and economics at the Harvard Graduate School of Education. “We’ve got a bunch of little things that we think are moving in the right direction, but we haven’t stepped back and thought, ‘O.K., how big an improvement are we really talking about?’ ” Professor Kane and I were discussing what he believes are the two areas that have the greatest potential for radically improving the way children are taught in the U.S. Both are being neglected by the education establishment.

The first is teacher quality, a topic that gets talked about incessantly. It has been known for decades that some teachers have huge positive effects on student achievement, and that others do poorly. The positive effect of the highest performing teachers on underachieving students is startling.

What is counterintuitive, but well documented, is that paper qualifications, such as teacher certification, have very little to do with whatever it is that makes good teachers effective.

“Regrettably,” said Professor Kane, who has studied this issue extensively, “we’ve never taken that research fact seriously in our teacher policy. We’ve done just the opposite.”

The second area to be mined for potentially transformative effects is the wide and varied field of alternative school models. We should be rigorously studying those schools that appear to be having the biggest positive effects on student achievement. Are the effects real? If so, what accounts for them?

Adjusting for demographics, our local school district (Cabrillo Unified, on the California coast south of San Francisco) ranks just about average among California schools. California ranks close to last nationwide, so that’s no cause for celebration. And the US overall ranks well down the list of developed countries.

The Knowledge Is Power Program (KIPP), to cite one example, is a charter school network that has consistently gotten extraordinary academic results from low-income students. It has worked in cities big and small, and in rural areas. Like other successful models, it has adopted a longer school day and places great demands on its teachers and students.

I know nothing about KIPP, but taking Herbert at face value, we shouldn’t be distracted by the “charter school” label. We know by now that charters do just about as well, or as badly, as our regular public schools. We should be verifying that models like this really work, and try to apply those models to more schools.

Said Professor Kane: “These alternative models that involve the longer school day and a much more dramatic intervention for kids are promising. If that’s what it takes, then we need to know that, and sooner rather than later.”

Children Left Behind

Derek Neal and Diane Whitmore Schanzenbach (University of Chicago) discuss their recent paper, “Left Behind by Design: Proficiency Counts and Test-based Accountability”.

Roughly two decades ago, education policy makers in the United States began to rely more heavily on standardized test scores as performance metrics for teachers and schools. During the late 1980s and through the 1990s, many states adopted test-based accountability systems that spelled out rewards and sanctions for teachers and principals as a function of the performance of their students on standardized tests, and when the federal government adopted the No Child Left Behind Act (NCLB) of 2001, test-based accountability became a nation-wide policy. The proponents of this development cite the need to bring “business practices” into public schools and the need to make schools “data driven” in ways that mirror the practices of private-sector companies.

In recent work [1], we explore a different effect of test-based accountability systems on the allocation of teacher effort, and we find evidence consistent with the hypothesis that test-based accountability systems not only shape decisions of teachers concerning what to teach but also whom to teach. We show that even though advocates of NCLB offered it as a remedy for disadvantaged children who receive poor service from their public schools, the design of NCLB almost guarantees that the most academically disadvantaged children will not benefit from its implementation and may actually be harmed.

Recently, the federal Department of Education allowed a few states to calculate AYP based, in part, on growth in student achievement during a school year rather than levels only. This is a step in the right direction, but without careful design work, these systems may simply create a different set of unintended effort distortions among teachers. Knowledge does not come on a natural scale, and given any particular scale, gains of a given size may be easier to achieve at some points on the scale than others. Thus, something as apparently pedestrian as the scaling of exams could have significant and unintended consequences for the allocation of teacher effort to different types of students if states do not carefully design value-added versions of AYP.

Because teachers are charged with fostering knowledge, character, and other things that are hard to measure, it is not obvious that incentive systems built around objective performance measures are even desirable strategies for monitoring teachers. Test-based accountability systems have nonetheless enjoyed strong support because school principals and others who monitor the performance of teachers in public schools are seen as agents of large bureaucracies that, especially in cities, have a long record of disappointing results. Nonetheless, our empirical results and the insights gained from research on the economics of organizations suggest that policy makers must tackle difficult design questions in order to construct accountability systems that deliver quality instruction for all students regardless of their aptitude and prior achievement. Policy makers should either take these design issues more seriously or follow the lead of many private sector firms and look for other ways to monitor and motivate teachers.

(Via Mark Thoma)

$6 billion “windfall” for schools?

From today’s SF Chronicle:

California schools are in line for a $6 billion windfall over the next five years, and interest groups are already lining up to get their share, promoting ideas like improving high schools, paying teachers more, and helping urban districts with severely declining enrollment.

The money is anticipated because K-12 enrollment is expected to drop while the state’s general fund revenues continue to increase. Several factors are contributing to the declining enrollment: Children of Baby Boomers are exiting the 5-to-17 age group, fewer people are moving into the state, and there has been a decline recently in the state’s birthrate.

How much of a “windfall” are we talking about here? With 6 million students in the system, $6 billion comes to $1000 per student. Spread that over five years, and we’re looking at $200 per student per year (never mind that we also have to assume that the economy stays healthy).

My local district, not atypical, spends about $7000 per student now. An extra $200 would of course be welcome, but it’s less than a 3% boost. Some windfall.

(Falling enrollment, by the way, has been a way of life in my district for the last ten years.)

School parcel taxes are bad public policy

Last June, a parcel tax proposal by my local school district failed, for the fifth time in recent memory. This Tuesday, Californians will vote on Proposition 88, an initiative that seeks a perpetual statewide $50/year parcel tax.

Sidebar: California School Funding

California school districts are primarily funded by the state, through a complicated formula that needn’t concern us here. As a consequence of Proposition 13 (1978), school districts are limited to parcel taxes to raise money locally for operating expenses.

In California, parcel taxes differ from ad valorem property taxes in that they’re assessed at a flat rate per parcel. Amounts vary; my local district’s requests have varied from $75 to $250 per year, generally for a period of five years.

(This 1997 report from the Little Hoover Commission is nearly ten years old, but it’s still the best treatment of K-12 funding in California that I’ve ever seen.)

Reliance on local parcel taxes to supplement public education funding is bad public policy, for two main reasons.

Parcel taxes are regressive

First, parcel taxes are regressive. Whether you live in a 10,000 square foot McMansion in Beverly Hills or in a shotgun shack on a postage-stamp lot, your parcel tax assessment is the same (if you’re only renting the shack, the parcel tax will almost certainly show up as a rent increase).

Parcel taxes are inequitable

Second, affluent school districts are much more likely than poor districts to be able to pass substantial parcel taxes, and so supplement California’s rather low level of state funding for education, leaving poorer districts stuck at the bottom. This flies in the face of the state supreme court’s Serrano decisions in 1971 and 1976 that basing school funding primarily on local property taxes is unconstitutionally inequitable.

Maybe in an emergency…

There is some merit in the argument that, during an acute budget emergency, a short-term parcel tax may be justified on the grounds that it’s the only recourse available to the district (or at any rate the least bad recourse). I accepted that argument, for example (and made it myself) in 2003, though not in 2006.

55%: even worse

Various people have advocated lowering the election threshold for a parcel tax to 55%, from the current Prop 13-mandated 2/3, as was done some years back for facilities bonds. That’s a bad idea, and more than a little disingenuous. Lowering the threshold for parcel tax measures requires a constitutional amendment. But once we’re amending the constitution, we’re no longer bound by the strictures of Proposition 13, and are free to restructure public school funding equitably. That is, if we’re going to pass a constitutional amendment, why not fix school funding right?

Fix it right.

K-12 funding in California is broken and needs to be fixed, and one way or another that will require higher taxes. But parcel taxes, whether local or statewide, are the wrong way to do it.

What about California Proposition 88?

A statewide parcel tax, as proposed by Proposition 88, largely avoids my second criticism; it will be collected (and presumably distributed) more or less uniformly across the state. On the other hand, it does nothing to address existing inter-district inequity.

Proposition 88 introduces a variation not found in local parcel tax proposals: no time limit. Local parcel taxes run for a few years, often five, and generally in the range of three to seven. But the statewide parcel tax proposed by Proposition 88 has no time limit at all. It would become a permanent part of California public school financing, embedded in the state constitution.

Because Proposition 88 includes a constitutional amendment, it could have implemented a more progressive revenue source (such as income taxes) instead of relying on regressive parcel taxes. It’s a bad measure, and should be defeated.