Overconfident in Elmhurst?

"We're competing against ignorance."
Donald Knuth

Tree City Leader welcomes rational free thinkers. With the local media catering to the status quo, Tree City Leader is proud to provide a private forum for news and opinions you will not find anywhere else. Tree City will reprint the best of the best as you will see below.

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The following was submitted to Tree City Leader on Monday, September 12, 2005 and is printed without permission

September 9, 2005

Jim Harris
Staff Writer
Elmhurst Press
800 Roosevelt Rd.
Bldg. D Suite 107
Glen Ellen, IL. 60137

RE: September 9th Article – “City Rejects Adopting Teardown Impact Fees”

I never thought I would need my old college statistics book, but after reading Mr. Borchert’s quote, “I am confident the numbers will continue to show that there is not a cause and effect relationship between teardowns and school enrollment,” I climbed up my bookcase and dusted off the old text. Just opening it made my head hurt but I was able to recall a couple of key fundamental principles before blacking out in a haze of complicated formulas.

A good statistical problem starts off with a hypothesis. In this case the hypothesis is, “increases in new home construction (i.e. teardowns) cause increases in District 205 student enrollment.” Before jumping right into the hard core statistics, one might do a little bit of research and look for potential cause and effect relationships.

Here is the result of my informal research (source: May 2005 Citizens Task Force Report to District 205 and walking around town with my eyes open):

From 1995 to 2004 enrollment increased roughly 1,100 students, or 17.5%, from 6,300 to 7,400. During the same time frame there were roughly 1,952 new construction permits.
This looks like a potential positive cause and effect relationship. Every teardown results in .56 new students. Looking around my immediate neighborhood, I see several new homes, all with more bedrooms and children than the prior owners. These new homes seem to help explain why Lincoln School across the street has grown from 466 to 509 kids in just the last year. Based on this informal research, it makes sense to do more rigorous analysis and discover how related these two variables may be.

The experts would probably graph data points and calculate relationships between variables. To assess correlations, a “Coefficient of Correlation” could be calculated and the result would be between -1 and +1, indicating perfect negative and positive correlation. A correlation of zero (as suggested by Mr. Borchert), suggests a complete lack of association between two variables.

Since each new student costs District 205 about $10,000, it is really important for arguments for and against impact fees or any other relief strategy to be based on solid analysis and statistical principles.

I suggest one of our local math teachers convene some students to analyze the data and make some conclusions. This would make a great extra credit problem and would provide the community with some objective, valuable information.

In the meantime, the laymen and politicians will fill the gaps with their own studies proving the old adage, “you can prove anything with numbers.”

Dan Spaeth