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October 2011

Detroit ranks 17th, Not First, in Crime

OR Ten Reasons Not to Trust Top Ten Lists


By Data Driven Detroit Staff

Data Driven Detroit’s mission is to provide up-to-date, objective information to inform better decisions.  Often that information is negative and our first inclination is to run away from it.  Accurate information is purely information that, whether negative or positive, should be accepted/acknowledged for what it is and serve as a basis for action.

However, when the information, or its analysis, is shown to be Inaccurate, it must be challenged!  Data literacy is best described as a general understanding of a dataset in respect to how it was gathered and how it was analyzed.  Debunking misleading analysis is one approach to improving data literacy.

On October 3rd 2011, Forbes released an article worthy of critique: America’s Most Dangerous Cities lists Detroit as Number 1.


1. The difference between apples and oranges:
Nine out of the ten geographies listed in Forbes’ piece are metropolitan statistical areas (MSA), but the included geography for Detroit is a metropolitan division (MD).  The Detroit MSA includes 6 counties while the Detroit MD includes only Wayne County; this is a difference of roughly 2.5 million people.  All this underlines a basic lesson from Statistics 101: DO NOT compare apples to oranges.  In this instance the apples-to oranges comparison hugely biases the results against Detroit by concentrating its crime.  When Detroit is properly included on the list as an MSA, it is actually ranked seventeenth in the nation for crime – not first!