Type K Error

What statisticians call Type 1 errors (incorrectly rejecting the null hypothesis) and Type 2 errors (incorrectly accepting the null hypothesis) initially arose from signal detection theory: is that blip on the radar screen a signal or just noise? The two errors were known to us engineers (my former life) as either a false alarm or a missed detection.

But these are not the only statistical errors that can occur. Andrew Gelman proposed two additional statistical errors, Type S (confidently stating that a value is positive when it is negative, or vice versa) and Type M (confidently stating that a value is small in magnitude when it is large, or vice versa). They have less to do with the actual statistics than with interpretation of those statistics.

In furtherance of Gelman’s extension of statistical errors, I’d like to propose a new one, the Type K error. This is in recognition of the attempt by Kris Kobach (Kansas Secretary of State and vice chair of a federal voter fraud commission) to deny the vote to (at least)  tens of thousands of US citizens in order to prevent the two or three improper votes (out of millions cast) from occurring. [My numbers may be off, but you get my meaning.]

There have been other manifestations of this “error” in recent days. A report detailing the economic consequences of admitting refugees did not include the overwhelming financial benefits they provide over the long haul. In other words, the Type K error might be defined as “the deliberate and wrongful act associated with a statistical evaluation of the effect of only one side of a policy.”

Author: Mike Maltz

Michael D. Maltz is Emeritus Professor of Criminal Justice and of Information and Decision Sciences at the University of Illinois at Chicago. He is currently an adjunct professor of sociology at the Ohio State University His formal training is in electrical engineering (BEE, Rensselaer Polytechnic Institute, 1959; MS & PhD Stanford University, 1961, 1963), and he spent seven years in that field. He then joined the National Institute of Law Enforcement and Criminal Justice (now National Institute of Justice), where he became a criminologist of sorts. After three years with NIJ, he spent thirty years at the University of Illinois at Chicago, during which time he was a part-time Visiting Fellow at the US Bureau of Justice Statistics. Maltz is the author of Recidivism, coauthor of Mapping Crime in Its Community Setting, and coeditor of Envisioning Criminology.

5 thoughts on “Type K Error”

  1. Maybe it should be the Barnburner Error after the legendary Dutch farmer who burned down his barn to rid it of rats?

    Barnburner has been used before in US politics.

  2. Could Donald Trump's effort to get to denuclearisation of North Korea by scuppering the agreement that denuclearised Iran, be called a Type K error?

  3. I don't know whether it could be construed as a Type K error, but one omission that continues to baffle me is the absence of mention that we (the U.S.) have made large investments in the health, well-being, and education of undocumented immigrants, DACA and otherwise. Why would we ourselves not want to reap the benefits of those investments instead of losing them to the countries that would receive them through our deportation of affected individuals? Are we capitalists, or not? I should add, this is not my top concern, personally; I just think it might help to make the argument that immigrants are contributing members of our society.

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