Wednesday, June 30, 2010

Detecting Bad Data

Political numbers geeks learned yesterday that Research 2000, one of the most prolific national political pollsters in recent years, may have been manipulating or even fabricating much of its data. This news comes less than a year after another national pollster, Strategic Vision, was exposed for probable fraud.

The evidence against these pollsters has come mainly from statistical scrutiny of their published results, performed by heroes like Nate Silver and Michael Weissman. But in most cases, you don’t have to be an accomplished sports statistician or a PhD physicist to detect bad data. You just have to care about numbers, and spend some time with them, and use a lot of common sense.

The sad thing is that in America today, hardly anybody cares about numbers except professional scientists and sports enthusiasts. Journalists, in particular, seem to think that their only job is to report both sides of the story--as if there’s no such thing as a fact. Except sports reporters, of course, who have to be extremely careful with facts and figures.

The good news, at the national level, is that the traditional media usually pick up the fraud stories after the bloggers do the actual work. The New York Times wasted no time reporting the Research 2000 accusations on its Caucus blog. If the accusations hold up, we’ll undoubtedly hear more. (Nate Silver will soon be assimilated into the New York Times. Let’s hope these kinds of stories don’t get suppressed in the process.)

Also, at the national level, there’s often enough honest fact-gathering that the frauds don’t make much difference. No single pollster had much impact on Silver’s bottom-line prediction of the outcome of the 2008 presidential election. The danger arises when everyone is relying on a single primary source, like the military or the White House.

At the local level, relying on a single authority is the rule rather than the exception. The Ogden Standard-Examiner almost always prints the word of local government officials as if it were fact, with no questions asked. Despite the detailed exposés on Weber County Forum, the Standard-Examiner has yet to report that the Ogden government manipulated its crime statistics, or that the government’s revenue projections for the Junction development were fraudulently overblown.

In science, fabricating data is the most serious of all crimes. I’ve given failing grades to astronomy students for fabricating their observations (which is usually easy to detect). There are continual allegations of fraud in medical research, where the financial stakes are incredibly high. Fortunately, the list of significant and documented cases of fraud in the physical sciences is extremely short. Although we physical scientists are just as human as everyone else, we know that our peers will tear our work apart if it doesn’t hold up to scrutiny.

Wednesday, June 16, 2010

APOD Celebrates 15 Years

Astronomy Picture of the Day, one of the very best sites on the Web, is celebrating its 15th anniversary today. My heartfelt thanks go to its devoted authors and editors, Robert Nemiroff and Jerry Bonnell--and to NASA for hosting the site.

APOD’s diversity is remarkable. The pictures include straight photographs, highly processed digital images, graphs, and even paintings. They come from professional astronomers, NASA, dedicated amateurs, scientifically inclined artists, and historical archives. The subjects go beyond pure astronomy to include the space program, earth science, and physics. Each picture comes with a short lesson, written by the editors, full of hyperlinks for those who want to learn more.

Although APOD is pitched to the general public, it’s also extremely useful to those of us who teach introductory astronomy, and to any scientist who needs a daily dose of breadth in this era of hyper-specialization.

Among Web sites, APOD is also remarkable for its simplicity: No banners, no sidebars, no drop-down menus, no fancy fonts. This is the Web as it was originally meant to be, where content takes precedence over presentation, and the hyperlinks are inserted by real human beings. The most noticeable change since 1995 is that the pictures have gotten bigger. They’ve also added Javascript rollovers to annotate some photos, and even an occasional video. And there’s now a linked forum where you can discuss the pictures. But simplicity still prevails.

Tuesday, June 8, 2010

Collected Works from Weber County Forum, Volume 2

About a year ago I posted a list of my Weber County Forum articles (loosely defined) over the previous three years. Since then the list has approximately doubled in length, so it's time for an update. Here, then, are my contributions since the middle of last June, in reverse chronological order: