Math and the Census

Mathematician (at U. of Wisconsin, Madison) and blogger Jordan Ellenberg has an editorial in The Washington Post discussing the merits of doing sampling and statistical analysis for the Census rather than trying to count every single person in the US.  As Dr. Ellenberg describes, despite their best efforts the Census Bureau makes mistakes:

But by the Census Bureau’s best estimate, the 2000 Census counted more than 5 million people twice and millions more not at all. Such errors crop up in every census, demonstrated visibly in 1940, when nearly a half-million more men registered for the draft than officially existed. And those errors aren’t demographically uniform; the bureau estimated that the 2000 Census undercounted the black population by about 600,000 while bumping up the number of whites by more than 2 million.

— Jordan Ellenberg

Like all things in politics, there is a lot of hot air and arguments on both sides.  But as Dr. Ellenberg points out, the really worry is that a lot of the people making decisions don’t know their math.  For example, “adjustment” is the use of statistics to fill in gaps in the count when people in a home aren’t able to be counted directly.  This is based on data and careful analysis, but you wouldn’t know it:

Sen. Judd Gregg (R-N.H.), who withdrew as the Obama administration’s nominee to be commerce secretary in part because of disagreements over the census. Gregg’s take on adjustment: “You take guesses based on what you think is the best political outcomes that you want, rather than counting people who actually exist.”

— Jordan Ellenberg quoting Senator Gregg

All us math folks know math is a changing field.   Many of the faculty and students in the OU Math department are doing brand new math every day in their research!  But everyday people think that Calculus is the last chapter in math (We can’t tell you how many times people have asked if doing math research is about doing really hard integrals!).  It turns out that Supreme Court Justices are no better informed than our grandparents:

But survey techniques of the kind the Census Bureau uses didn’t exist before the 20th century, and only recently have they been refined enough to improve the accuracy of the census. Justice Clarence Thomas, in a 2002 opinion on sampling, asked: If the Founders had meant the Census Bureau to use statistical sampling technology to improve its count, wouldn’t math whiz Thomas Jefferson have used it in the first census? The question is nonsensical. Jefferson could no more have done so than he could have surveyed the population from space.

— Jordan Ellenberg

To read the full article go here. And be sure to check out the comments to see how hot headed people get on the seemingly boring subject of the Census!.