Comments, observations and thoughts from two bloggers on applied statistics, higher education and epidemiology. Joseph is an associate professor. Mark is a professional statistician and former math teacher.
How to prevent huge teacher layoffs, by Christina D. Romer, Commentary, Washington Post: The emergency spending bill before the House would address the education crisis facing communities across America -- and the jobs of hundreds of thousands of teachers are at stake. Because ... state and local budgets are stressed to the breaking point..., hundreds of thousands of public school teachers are likely to be laid off over the next few months. As many as one out of every 15 teachers could receive a pink slip this summer...
The deficit hawks generally talk about the fate of our children when making the case to reduce the deficit, but at a time like now when the recession is pressuring school budgets, how are kids helped by reducing their educational opportunities?
It used to be fun reading Molly Ivins skilfully mocking hypocritical politicians trotting out the "What about the children?" line. Now she's gone. They're still here.
In a recent post, Dead Dad wrote about DIY-U. And he's right -- most academic training (especially in areas like Epidemiology) benefits greatly from an institutional framework. But there is another angle that I think is worth thinking about -- school should not be the only place from which you derive learning. There are huge advantages to being well read and interested in a wide range of subjects. It's not an optimal strategy to take a degree in every area you have any kind of interest in.
So let us try and take the good part of this bad idea -- lifelong learning is something that it is important to begin early and never really stop doing!
Brian (who blogs on television and society at Ultrasonic Remote) sent the following example of winnowing processes gone awry by the always sharp Gail Collins. Collins seems to doubt that the GOP primaries are selecting their strongest candidates:
Pretend you’re the Republican leadership in a smallish state with an open United States Senate seat. The opposition is running a popular, longtime officeholder whose sense of inevitability was shaken by recent revelations that he had referred to himself as a Vietnam War veteran when he isn’t one.
Your own options are:
A) A well regarded former congressman who is a decorated Vietnam War veteran.
B) A political novice who made her fortune building up an entertainment business that specialized in blood, seminaked women and scripted subplots featuring rape, adultery and familial violence. In which the candidate, her husband and children played themselves. Also, the family yacht is named Sexy Bitch.
Well, obviously, you go for the yacht owner.
Yes, this week the Connecticut Republican Party chose Linda McMahon, the former C.E.O. of World Wrestling Entertainment, to be their Senate candidate. Her main opponent, the former Representative Rob Simmons, packed up his war medals and went home.
“You can’t argue with arithmetic,” he told The New London Day.
The math in question is $50 million, the amount McMahon claimed she was prepared to spend on her campaign. Connecticut has just under two million registered voters, so maybe she’ll just invite everybody in the state to a nice dinner at Red Lobster.
So far this season, the Republicans have offered two new models of their future. One is the Tea Party vision, in which outsiders full of spirit and excitement overthrow the old order. In North Carolina, there was so much spirit and excitement that voters gave the top spot in a Congressional primary to a former drug addict who, according to court documents, once referred to the United States government as the Antichrist and claimed to have personally located the Ark of the Covenant.
...
“One good thing has come from her run: Vince McMahon putting out an edict that there will no longer be any cutting of your foreheads with razor blades,” said Superstar Billy Graham, a retired wrestler who contracted hepatitis from a bloody competitor. “He has actually stopped wrestlers from cutting their heads with razor blades. This is a big deal!”
As reported on This American Life (get a download here. It's well worth the money), back in 2002, recently retired multi-millioniare Steve Poizner volunteered to teach a class in east San Jose. A few years later he wrote about that year in the book Mount Pleasant: My Journey from Creating a Billion-Dollar Company to Teaching at a Struggling Public High School. It's an interesting account (though not in any of the ways Poizner intended).
One detail struck me as particularly funny as I listened to the story while driving through LA. Here's the excerpt as Poizner read it on the show:
Several miles and a couple of highways later I took the Capital Expressway exit and drove into what felt like another planet. Signs advertising janitorial supply stores and taquerÃas. Exhaust hung over 10 lanes of inner city traffic; yellowing, weedy gardens fronted many of the homes, as did driveways marred by large oil spots or broken down cars.
Taquerias are generally small restaurants that serve mainly tacos and burritos. After hamburger joints, they are probably the most common restaurants in California. The thought that a California resident who wasn't looking for a place to eat would even notice them is odd. Listing them as an exotic sign of urban decay is downright bizarre.
Andrew Gelman has a great post on how statisticans do not always apply the lessons of statistics to their everyday lives. And it is true -- a lot of what we do in our lives is from custom and tradition that has never undergone rigorous evalaution. I'd be curious to see how teaching would change if we tested pre- and post-class knowledge (and had a control group who did not take the class). One suspects that the results might be humbling . . .
This reminds me of Miquel Hernan arguing in the journal Epidemiology (sadly, gated) that epidemiologists should be skeptical of journal impact factors because of our training. Unfortunately, despite this skepticism, it is rare for an active researcher not to have a good idea of the ranking of various journals (often based off of the impact factor). I think that staticisticans are better at disregarding impact factors but that's not a universal rule.
But I wonder if we could improve a lot of everyday tasks with a slightly tigher focus on statistical and/or epidemiological reasoning?
This is either the best piece of California political reporting I've come across recently or the best piece of education reporting. Either way it's worth the ninety-nine cents.
I've been enjoying this online discussion (particularly the contributions of Felix Salmon) and I'm sure Joseph and I will have more posts on the subject but first I have something I have to get off my chest:
No one can possibly know what's going on here! We can get some smart people making good guesses about long term stock performance, but these guesses are based on data from a century's worth of secular upheavals. A list that includes the Great Depression, two world wars, a post-war reconstruction, the cold war, China becoming a major player, boomers entering the market, boomers leaving the market and huge changes in regulation, technology and business practices.
What's happening now never happened before. What happened before never happened before. What happened before what happened before never happened before. We have no precedents. People are recommending forty-year investment strategies using models based on data from markets that haven't gone twenty years without a major secular change. . There. I've got it out of my system. Go on with what you were doing
We've been speaking about investment and stock market returns recently as an example of how forecasting is difficult. But I would be remiss not to mention Vanguard and it's very articulate founder. I've just finished reading his latest book (Enough) and it was very worth a couple of hours of time. A very thoughtful reflection on character and ethics.
I'm also hoping to emulate him in another way -- he is 91 years old and still active in what he loves. Here is hoping I'm still doing Epidemiology at the same age!
Candid Engineer points out something that I think all of us find as a challenge -- actually getting work out in the form of papers. I like to solve puzzles and understand the world around me. It's what drives me as a scientist.
On the other hand, it's a minority of results that are fun to write up and the publication process is always painful. So I, too, have to watch the tendency to learn the results and then move on. This is specially true if you take on a high risk project and the results are a bit disappointing.
My most recently submitted paper was analyzed 2 years ago and it took a lot of effort to clean it up until it could be submitted. Not a fun process.
But sticking with it is crucial. It's the only way to really let others know what you have done and really push science forward!
That sounds sarcastic but it's not. We really are blessed with an amazing crop of writers who can discuss business and economics with insight, encyclopedic knowledge and surprisingly good prose.
Here a couple of the best get us up to speed on financial reform: Preventative Measures
Mark points out, in a comment on my post on financial literacy, the issue of the equity premium as being discussed by Felix Salmon. I think that this point is really interesting and deserves more attention than a breif comment.
This article from the Economist is another great discussion of the complexities of making this claculation. The author lays out the basic problem with calculating an equity premium (or lack thereof) using current data (i.e. recent rates of return). One does not want to price in the current economic crisis (unless one thinks that these crises will be more common in the future) but neither does one want to calculate an equity premium that ignores either key events or actual real rates of return.
When you add in the issue of limited data (we only have a couple of hundred years of annual stock returns for the United States and only about 60-80 years are really relevant to the current market) and the risk of a secular shift (what if one or more financial innovations has fundementally changed the nature of the market) then these complications are almost enough to make the problem intractable. One might argue that these factors need to balance out in the long run (if equities don't pay a premium for risk then people will stop holding equities). But it is remarkable how long the long run can be; I think John Maynard Keynes said it best with:
The long run is a misleading guide to current affairs. In the long run we are all dead. Economists set themselves too easy, too useless a task if in tempestuous seasons they can only tell us that when the storm is past the ocean is flat again.
I think that this problem is true for epidemiological forecasts as well. The forecast of influenza rates (as a recent example) depends critically on the assumption that the current strains of influenze are not fundementally different than past strains. Often this assumption is reasonable but it can miss the most important changes (like the arrival of a new and more lethal version of the virus).
Whether it is disease rates or stock markets, it is not a simple matter to use the past as a guide to the future. There is no doubt that forecasting is hard but it's also true that it is important to do it as well as possible. If I ever figure out the trick I will be sure to share it!
Talking Points Memo has been doing a superb job covering the races in Kentucky and Pennsylvania. Josh Marshall's posts on Rand Paul have been particularly insightful. You really ought to take a look.
That has nothing to do with the main point of this post but I feel guilty hammering away at TPM and I'm afraid it's time to pick up the old nine-pounder again and start swinging at this:
Whitman's support has fallen in large part due to Democratic attacks over her connections to Goldman Sachs -- the Dems would prefer to face Poizner in the fall. There may also have been a backlash against her big personal spending on the race, which has reached $68 million so far, and a tightly controlled media operation in which she has avoided directly answering questions from reporters about the issues -- a fact that is frequently noted in media reports.
As statisticians, we are constantly being asked why something happened. We don't like the question (the subject of causality makes us nervous) but it's not something we can avoid so we approach it as rationally as we can. We look at correlations, of course, but we also look at timing, magnitudes, precedents. We consider the implications of the different hypotheses (for example, if bad weather caused a shift in behavior, that shift should be limited to certain regions). We seek out the opinions of informed sources while taking pains not to get sucked into conventional wisdom. We survey the situation on the ground and use that most important of statistical tools, common sense.
I'd like to say that the final step is testing the hypothesis, but that's not usually the way it works. When it comes to questions of causality, the final answer is usually just an educated guess. Fortunately, most of us have gotten to be pretty good guessers.
How does the Goldman Sachs hypothesis stand up to this (admittedly unscientific) approach?
For starters, the timing is all wrong.
(I'm assuming these are mostly likely-voter polls)
The Goldman Sachs-Whitman connection came out in February. The Abacus scandal hit big in mid-April. Poizner's Vulture ad was released at the end of April. Which of these would you associate with an inflection point in Whitman's support?
By comparison, the news for much of April had been dominated by Arizona's immigration law (which passed their house on April 13th) and since March, Poizner had been running ads attacking Whitman as being soft on immigration.
How about magnitude and precedent? Whitman took a fifty point lead down into the single digits. Immigration and RINOism are huge issues for the California GOP. Either could easily kill a campaign. The Goldman Sachs story, on the other hand, is abstract, relatively minor, and only tangentially related to the issues California conservatives care about.
And has anyone EVER burned off forty-plus points of lead because of this kind of business deal?
And finally, do any of the major players, the ones with access to internal polling, actually believe this hypothesis? Poizner clearly doesn't or he'd be making more than passing references to Goldman Sachs. Meg clearly doesn't or she wouldn't be spending her time insisting that she supports neither amnesty nor Senator Boxer. Hell, even the CDP doesn't or they wouldn't pick Peter Coyote to pitch their case. (I'm not saying that the CDP ads are ineffective; I'm saying they are targeted at the general election.)
To make this even less scientific, here's my good ol' boy take on what happened. It's the old story of an out-of-towner walking into a bar, hearing a couple of locals bragging and believing every word. ("You mean you really took down a $70 million dollar campaign?" "Yep, and we did it with just one little website.")
I suppose there's no harm in a little boasting (and it's not something that Democratic operatives get to do that often in California). I just hope that the people at TPM are a bit more worldly the next time the situation comes around.
And to close out the subject of nine pound hammers (and get our minds on something more pleasant than politics), here's a mental health break from a friend of mine:
Update: Ed Kilgore has a good analysis of the race here. I think he gives too much weight to the Goldman Sachs story but I may still just be stuck in argument mode as a reaction to TPM.
Olivia Judson has a new piece on archaea, those strange life forms that can adapt to the harshest conditions on earth. I've read a number of other articles on the subject but most of them had an empty calorie quality, heavy on the gee-whiz and light on the substance. But Judson focuses on the good stuff. How do archaea differ from other life? What do we know or suspect about their evolution? Why have they been so difficult to study?
This is not an isolated case. I have often looked at the topic of one of Judson's pieces and thought "Not that again," but I always felt I owed her an apology by the time I got to the end.
I know that spousal hiring is a contentious topic and, like many complicated transactions, it is hard to carefully audit all elements of it. I am sure that situations happen that are not ideal. That being said, I do love it when I see a heart-warming story of it all working out and everyone (University included) being better off.
