Wednesday, February 29, 2012

Teacher ratings

I have been very busy on other things so have only had time to scan the articles over the past week about the release of New York City teacher ratings. One item really jumped out at me, and that was the wide range of the confidence interval for the teacher ratings. As Michael Winerip puts it in his excellent column, posted yesterday (but in today's hard copy paper):

For example, the margin of error is so wide that the average confidence interval around each rating for English spanned 53 percentiles. This means that if a teacher was rated a 40, she might actually be as dangerous as a 13.5 or as inspiring as a 66.5.
Think of it this way: Mayor Michael R. Bloomberg is seeking re-election and gives his pollsters $1 million to figure out how he’s doing. The pollsters come back and say, “Mr. Mayor, somewhere between 13.5 percent and 66.5 percent of the electorate prefer you.”
 More to come on this issue, I think. But Winerip's column is a good place to start.

Update, March 4: I always maintain that you can't analyze or understand data without knowing or understanding the context. Here's a very interesting Op-Ed by a teacher, on that provides some much-needed context.

A useful map from the NY Times

Update, March 7: Here's a link to Mayor Bloomberg's press conference and press release announcing the results of the first 18 months of grades: the percent of restaurants with A grades has increased to 72%. The incidence of salmonella in the city has decreased. Most of the key violations declined. You can get DOHMH's full report here as a pdf. Here's a screenshot of the trends reported salmonella graph:

Source: NYC DOHMH 
The focus on outcomes is refreshing and very useful. 

The NY Times has mapped New York City's restaurants, coding them according to their NYC Department of Health (and Mental Hygiene, to give its full title) cleanliness rating system. Here's a screenshot of our local restaurant row:


The blue dots are A grades; the green dots are B grades. When you roll your mouse over the dot, you get the restaurant's name grade, and the number of violations; you can click on the map and get details (perhaps more than you want). You can filter by grade, type of violation (vermin, insects, personal cleanliness, chemicals, or food temperature) and by type of cuisine. And, like any map, you can zoom. My only complaint is that once you have a location, you can't move by clicking on the edges of the map, you have to type a new location into the app. It's a great service - I wouldn't pick a restaurant using only this information, but it's a great way of presenting it.

Monday, February 27, 2012

Big data roundup

Update, March 4: Here's an article in the NY Times about an exciting use of integrated big data, a series of programs IBM designed for Rio de Janeiro.

There has been a series of articles in the past couple of years about the era of big data we've arrived in, including today's NY Times article about Facebook's efforts to manage its stream ("firehose" is the term the NY Times used) of user data in the face of privacy concerns. McKinsey recently compiled a chart showing the potential some sectors of the US economy have for using big data:
Source: McKinsey and Company

Not-for-profits that provide social services, including mental health, health, or other social services have been collecting large amounts of data for years, but many have had trouble unlocking its potential for any number of reasons. Yet analysis of large amounts of data can allow providers to test interventions and make better management decisions, improving productivity and services.

The McKinsey Global Institute analyzed data in five domains, including health care in the US and the public sector in Europe, and concluded that big data can generate value in each. These conclusions seem easily extendable to the not-for-profit sector in the US, and I recommend reading McKinsey's full report or at least the executive summary, both available free, after registration here. A shorter version of the executive summary, focusing on strategy, is available as an article here. The basic points are:
  • the era of big data is here, allowing providers to collect data across units, integrate information, and analyze the information;
  • big data can change the way you do business, making processes and information transparent;
  • you can use data to experiment and test hypotheses;
  • privacy is already a concern;
  • managers will need to understand big data, and will need specialists who can provide analytic support.
 These are big questions. But it's not too early to start thinking about them.

Wednesday, February 22, 2012

"The Drunkard's Walk: How Randomness Rules Our Lives," by Leonard Mlodinow

Towards the end of his wonderful book "The Drunkard's Walk: How Randomness Rules Our Lives," the physicist Leonard Mlodinow quotes Max Born:
Chance is a more fundamental conception than causality.
And that's what Mlodinow has been proving, as he takes the reader on a road trip through the history of the development of modern techniques of statistical analysis, with some detours into personal reminiscence along the way. Starting from the concept of randomness, and moving through the basic principles of probability, the development of statistical explanations, and the law of large numbers, Mlodinow wears his learning lightly, and expresses it well. His explanations of the theory behind technical concepts like the law of large and small numbers, standard deviation, and variance are clear.

Human beings like to identify patterns in events, but our intuition often fails us. Seeing patterns where there were really just random events can result in large-scale shared illusions: Mlodinow cites the late 19th century craze for seances as an example. He discusses the availability bias -- the tendency to give available memories extra weight -- in simple, memorable terms, and shows how details that fit our mental picture add credibility to a scenario. He does the same thing with confirmation bias, the tendency to search for a way to prove that an idea is correct, while ignoring ambiguous or contradictory evidence. Mlodinow gently takes the reader to his conclusion that in random variation there may be patterns, but the patterns are not always meaningful. And then he offers some useful ways of overcoming our natural inclination to error:
1. Remember that chance events can produce patterns.
2. Question perceptions and theories.
3. Spend as much time looking for evidence that you are wrong as you spend looking for evidence that you are right.
I've discussed these concepts before, but they're worth repeating. And Mlodinow takes a theoretical approach, while remaining completely accessible to the general reader. It's a fascinating book, well worth reading.

Monday, February 20, 2012

A couple of interesting articles from the weekend

The NY Times Magazine carried not one but two interesting articles yesterday. The first, by Charles Duhigg, about how companies learn from and exploit your shopping habits, is here. It's pretty interesting, because whether or not you are curious about the numbers, everyone, here in the US at least, has to shop.

The second article is Nate Silver's "Why Obama Will Embrace the 99 Percent," part of a series he's working on for the Magazine in conjunction with his blog. It's a fascinating comparison of the comparative electability, as they look now, of Republican Presidential hopefuls Mitt Romney and Rick Santorum. It's clearly written, with good graphics, including an interactive chart looking at chances of winning the popular vote in varying economic (and presidential popularity) circumstances, and well worth reading.

Friday, February 17, 2012

Outsiders and data analysis

Here's a nice little article from the NY Times Sports section, describing the role outsiders -- who are not acculturated to an organization's biases or mindset -- can play when they take large datasets and start thinking about them. The article hook is a freelance analyst (and FedEx truck driver) who predicted at the time of the 2010 draft that Jeremy Lin would be a good point guard. Two things to keep in mind: the more data sets out there, the more people there are who can look at them. And if more people looking at them, more good ideas are bound to appear.

Thursday, February 16, 2012

Code for America

You've probably heard of Teach for America, and VISTA, both of which place recent college graduates (and others) in teaching and service jobs, respectively, in high need areas. Now there's a new organization called Code for America, which pays recent college graduates a small stipend to work with city governments "to build and enhance Internet tools that bolster civic engagement." Code for America works with partner cities--this year they include Austin, Detroit, Chicago, New Orleans, Honolulu, Macon, Philadelphia, and Santa Cruz--and provides them with techies--CfA Fellows--who help them solve data problems. The Fellows program solutions, some for the cities, and others shared on the Code for America website.

Code for America's Brigade calls on developers, designers, and community leaders to use the web, and available government data, to address problems by developing apps, sometimes with the support of the fellows. And the apps are pretty great. SnapFresh helps users find retailers who will accept food stamps by texting their location: the app will text back addresses of and directions to the five nearest food stores. (It works by text. you don't need a smartphone.) It works in every city in every state in the country. Where's My School Bus? allows Boston parents to track their kids' bus (the app requires the Boston Public Schools to verify that the user is a parent or guardian). Lunch Roulette  arranges lunch dates among employees within organizations who might not otherwise meet.

An incubator for startups that will draw on open data to provide faster, better and easier services will launch later this year.

Wednesday, February 15, 2012

It's an election year! Time to start obsessing about polling

Let's start with Presidential approval ratings.

According to a CBS News poll released yesterday, President Obama's are up, reaching 50% for the first time since May, 2011:


CNN's polls say the same thing. So do Rasmussen Reports, which says that 49% approve of the President, and that 49% disapprove. They display the data differently:

What's going on here? I suspect it's in the way the questions are asked and the data tabulated. If CBS and CNN subtracted the lukewarm approvals from the strong approvals, you might get the 27% strong approvals that Rasmussen reports. But it appears that right now there are more people expressing strong and lukewarm approval than there are expressing disapproval. The takeaway? If you can, look at more than source for information. And think about how each organization is reporting its data. And right now, in a head-to-head competition, even Rasmussen reports that Obama beats Santorum and Romney.

Which is what Nate Silver, of FiveThirtyEight (now a part of the New York Times) reports as well. I should say that's what Silver concludes, as he is using an early stage model taking account of the economy, each candidate's ideology, and the approval ratings. He also has some projections about upcoming Republican primaries (in Arizona, Michigan, Georgia, and Ohio). FiveThirtyEight is a great site, and I'll be keeping an eye on it in the coming months. Even though the election is still nine months away.

Monday, February 13, 2012

Safety net issues

Update February 17: Here's a link to Paul Krugman's column on this article, titled "Moochers Against Welfare." It's worth reading all the way through to his apt conclusion.

In case you missed it yesterday, or read it before you had your coffee, take a look at this NY Times article about the increasing reliance on government programs around the United States. The reporters took a hard look at entitlement programs and who uses them. The tables are pretty good, and the interactive charts are even better, allowing readers to click on any county in the US and to see transferred income per capita, the share the transfer income is of all income in the county, and a comparison to the US average. The takeaway is that everyone uses government entitlements, including those who object to them.

Here's a screenshot of the map, showing Sumter County, Alabama, which I chose randomly:


The maps also break out different entitlements programs, including Social Security, Medicaid, Medicare, Income Support, Veterans Benefits, and Unemployment Insurance. (It would have been helpful if the Times had included numbers of people receiving benefits, but they didn't.) And the article includes a nice statement by a political scientist about how the states that receive more benefits than they pay in taxes tend to vote Republican, while states that pay out more than they receive tend to vote Democratic.

There's an argument being made that the inclusion of veterans benefits is a mistake, as they are earned by service to the country, and in any case drive up payment of government benefits in the south. I disagree with the first point (and let me be clear, I am not arguing against payment of benefits to veterans, I just see no reason not to include them in this analysis). As for the second, according to the Times, veterans benefits account for only 0.4% of personal income in 2009, compared to 17.6% for all government benefits. That's too small to drive any of these numbers.  There has been a series of articles recently about the transformation of the VA medical system into a model of good care. Here's one from a couple of years ago.

Friday, February 10, 2012

Education inequality

Today's NY Times carries a story about several studies, collected by the Russell Sage Foundation into a book, about the rising inequality in education based on income. It's interesting, and that's because the recent studies show that family income, not race, is the biggest dividing factor in achievement. The first chapter is available online, as are the tables. They're worth looking at (and much better than the partial table published in the Times). Here's a screenshot of one table, illustrating enrichment expenditures on children by income quintile:

Source: Russell Sage Foundation

Take a look at the tables, and the first chapter. I found them pretty depressing. But if you draw another conclusion from them, let me know by commenting.

Wednesday, February 8, 2012

Open data, gathered at one site

The US Government's open data site, data.gov, subject of an earlier post, now links to open data sites from foreign countries, states, and local governments. Even though the data provided by different governments are a mixed bag, it's a very useful site. Colorado, for example, has a beautiful photograph illustrating its site, and provides a collection that includes Colorado hospitals, private schools in Colorado, and the Colorado lottery numbers.

New York State's link take you to the State Senate data set, which might be fun to explore - one dataset that I downloaded is the NY Senate web analytics, which lists the number of Facebook fans each Senator (with a Facebook presence) has. New York City provides nearly 1000 datasets, including the average SAT scores of 2010 high school seniors in the city's public schools. Indiana's link - yes, I tried it - doesn't load properly.

Of the international datasets, Australia's is pretty great. It includes a link to apps that developers have created from the data. The screenshot at the top? That's a pretty important one.

Tuesday, February 7, 2012

Ross Douthat and Abortion

Ross Douthat had a column in Saturday's New York Times called "The Media's Blinders on Abortion," arguing (1) that the media generally ignore the fact that the United States is becoming more anti-abortion, and (2) that Planned Parenthood's downplays abortions as a percentage of its services.

A lot of people commented on various aspects of the piece, including the fact that Douthat has never had to decide to terminate a pregnancy. Several also stated, correctly, that Planned Parenthood provides health care for many low-income women across the country. I want to comment on Douthat's use of statistics, because I think he's cherry-picking.

First, here's what he says about American attitudes:
In the most recent Gallup poll on abortion, as many Americans described themselves as pro-life as called themselves pro-choice. A combined 58 percent of Americans stated that abortion should either be “illegal in all circumstances” or “legal in only a few circumstances.” These results do not vary appreciably by gender: in the first Gallup poll to show a slight pro-life majority, conducted in May 2009, half of American women described themselves as pro-life.
Yes, Gallup reports that in May 2009, slightly more Americans reached in its "Values and Beliefs" survey called themselves "pro-life" rather than "pro-choice" (51% to 42%). But the report goes on to say that, as has been true for many years, most (53%) of Americans felt that abortion should be legal under certain circumstances. (There is a lot of variation among which circumstances.) But that was two years ago. The most recent (2011) poll still shows that most Americans believe abortion should be legal under some circumstances. The percent of Americans saying abortion should be illegal under all circumstances has ranged, since 1975, from a low of 13% to a high of 23%. In 2009 it was, guess what, 23%. By 2011 it had dropped back to 20%. These are probably normal fluctuations due to polling issues, and Douthat should have reported them. (I use "Americans" in this paragraph, as Gallup does on its website, but the correct term is probably "respondents.")

Here's what Douthat says about Planned Parenthood's services:

It’s true that abortion is only one of the services Planned Parenthood provides. . . But abortion is hardly an itty-bitty and purely tangential aspect of its mission, as many credulous journalists have implied.
Planned Parenthood likes to claim that abortion accounts for just 3 percent of its services, for instance, and this statistic has been endlessly recycled in the press. But the percentage of the group’s clients who received an abortion is probably closer to 1 in 10, and Planned Parenthood’s critics have estimated, plausibly, that between 30 and 40 percent of its health center revenue is from abortion.
By way of comparison, the organization also refers pregnant women for adoption. In 2010, this happened 841 times, against 329,445 abortions.
Planned Parenthood, the parent organization, provides aggregated, summary information about services provides from its affiliates throughout the country. (The affiliates decide which services to provide. Some provide abortions, but others don't.) That aggregated information is the source of Douthat's claim. The 2010 summary available as a pdf here, but I'll post a screenshot:
It appears that Douthat's claim that abortion might be as much as 10% of services is based on comparing the 330,000 abortions to the 11,000,000 different services Planned Parenthood provided. Did he do the math wrong? In any case, it's an apples-to-oranges comparison: some patients may have received more than one of the services.

But it's more important, once again, to consider the context. The Alan Guttmacher Institute reports that the number of abortions per 1000 women aged 15-44 has been declining; in 2008, the latest year for which figures are available, that was 19.6 per 1000, down from a high of 29.3 per 1000 in 1981. In 2008, 1.21 million abortions were performed in the United States. The average cost per non-hospital abortion under local anesthesia (ie, most abortions)? Under $500. Remember, also, that 87% of US counties, where 35% of US women reside, did not have an abortion provider. That means that those sites that perform abortions, Planned Parenthood among them, perform more than their share of abortions.

I could go on. (Like Douthat's suggestion that it's somehow weird that Planned Parenthood refers women for mammograms? So does my Park Avenue ob-gyn. It's not like getting a dental x-ray). But if someone is going to take on an organization like Planned Parenthood over statistics, they need to do it right.

Thursday, February 2, 2012

College applications in the US - Early Admissions

This is the second in a series of posts about the college admissions process in the US. You can read the first post in the series, a general discussion of the landscape, here. Today I am going to talk about early admissions policies at selective colleges.

There are basically three kinds of early admissions programs. Under binding early decision (ED) programs, the student commits to withdrawing all other applications and attending a college if admitted. Under early admissions (EA) programs, students signal a keen interest in a college but do not have to commit to attend the college if admitted. Under rolling admissions programs, colleges start admitting students early in the year, then keep admitting students until a class is filled. Rolling admissions programs are non-binding. Large state universities often use rolling admissions programs.

If college admissions are a geologically active landscape, Early Decision is one of its volcanoes. Parents and students have learned that applying early under a binding ED program can increase the chances of admission, and academic studies bear this insight out. But students who are admitted to more than one college, in the spring, can pick among (or negotiate) financial aid awards, an option that is foreclosed under binding ED programs. Since students applying to early may get a significant admissions advantage,* that's a significant trade-off. 

Thus whether to apply early, and where, are two important decisions applicants make early in the fall of senior year. But it's not a simple decision. The book “The Early Admissions Game: Joining the Elite” (2003) by Avery, Fairbanks, and Zeckhauser makes clear that despite the admissions advantage, simply applying early does not necessarily increase a student’s chances of acceptance. The authors advise: look for a good match and understand that their key insight is that “applicants stand to gain most from applying early when they have moderate chances of admission in the regular process.” If a student has only a poor chance of admission in the regular process, then applying early will not help; if the student has a good chance of getting in during the regular process, then he or she will probably be admitted later in the spring. 

So the application has to be to the right school that is a good match for the student. And on top of all the other challenges, extremely selective colleges keep changing the game. Yale and the University of Chicago have non-binding Early Action programs. In 2006, Harvard and Princeton ended their early decision programs. In 2011, they reinstated them, as non-binding Early Action programs.

What is happening this year? The New York Times reports an increase in the number of early applications in the fall of 2011; Bloomberg News reports a decrease in the overall number of applications. It appears that Harvard and Princeton’s reinstatement of Early Action programs may have resulted in fewer applications to other Ivy League schools. On the other hand, because of its reinstated program and its outreach efforts, Harvard reported greater diversity in its early action applications in the fall of 2011 than it had seen in the past:
Compared with the Class of 2011, when 4,010 applied early, African-Americans now comprise 9.1 percent of the pool, a 61 percent increase; Latinos comprise 9.1 percent, a 31 percent increase; Native Americans make up 1.1 percent, a 29 percent increase; and financial aid applicants are nearly 72 percent of the pool, a 9.4 percent increase.   
It may be that two new trends are becoming evident: more students may be applying early, and they may not be applying to as many colleges overall. That number is still to come.  (Unfortunately I cannot seem to format this footnote properly.)*About that advantage. Avery, Fairbanks, and  Zeckhauser put it this way in “The Early Admissions Game”:
Applying early provides a significant admissions advantage, approximately equivalent to the effect of a jump of 100 points in SAT-1 score. Applying early to an ED school provides a slightly larger advantage than applying early to an EA college.  . . . Moreover, we find that the claim made by some colleges that the pool of early applicants is much stronger than the pool of regular applicants is part exaggeration and part myth. Early applicants have slightly higher test scores and high school class ranks than regular applicants at the most selective EA colleges, but early applicants tend to be slightly weaker in these qualifications than regular applicants to ED colleges.

Wednesday, February 1, 2012

College rankings scandal

There have been several articles this week reporting an admissions dean's efforts to inflate the SAT scores of incoming students, apparently in order to influence the US News and World Report rankings.
The main details: the school is Claremont McKenna College in California; the collective scores were apparently inflated by 10-20 points, and the admissions dean has admitted his actions and resigned.

Here is a roundup of some of the articles from the NY Times, the LA Times, and Bloomberg.

I know that lots of questions remain, but in my view, the real scandal is the too great weight given to those rankings, and I intend to make them the subject of one of my posts in the series about college admissions (yes, I'm really working on it). Here's a link to a great article in the Washington Monthly about the pernicious effect of the rankings. It was published nearly 12 years ago, and what has changed? Very little (though the USN&WR does disclose more of the methodology of its ranking system). Click here for the Washington Monthly's "different kind of" college ranking.

Oh, and if you really want to know what's going with a college? If your child is applying, visit! Talk to students and faculty, and let your child spend the night in a dorm. And take a look at the college's common data set, usually available on the website. Here's a link to Claremont McKenna's.

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