Volume 33, Number 7, July 1998


Issue at Hand

Read ‘em and Weep

by Debra Levy

One of the best text books I ever read in college was a thin little one called "How to Lie with Statistics." The bright orange paperback, which is still in print, detailed the myriad of ways in which statistics are manipulated by the unscrupulous in order to support a particular point of view or program. While I can't remember whether I read it for a Math or Psych course (alas, the memory fades after all these years), I can vividly recall a class in which our professor used the same set of statistics to argue two totally opposite theories convincingly. Oh sure, the emphasis changed and the graphs looked entirely different, but only one set of stats was used.

This experience has led me to always approach statistics with usual journalistic jaundice. Of course, things have changed over the years, and we are all a bit more jaded in our approach to information. If same book were published today, it might be called "How to Spin with Statistics, " and no one would blink an eye.

But despite all the spin and manipulation, we do put a fair amount of reliance on statistics because they do, in their pure form, provide empirical information in a relatively objective manner.

This was how I looked at the recent Producer Price Index data that showed the percent of change in prices of selected building products during the past 16 years. All materials were measured in the same time frame, subject to the same inflation rates compiled by the same organization, in this case the U.S. Commerce Department.

Here's how much the prices of products have changed from March 1982 to March 1998:

Lumber + 81.9%
Gypsum + 72.1%
Cement + 40.9%
Metals + 27.1%
Flat Glass - 2.5%

Now you probably expect me to offer some cogent explanation as to why glass seems to be the only material in the negative category. Could it be changes in technology? Well the last great advancement in manufacturing was the development of the float process, a feat accomplished more three decades ago. Could it be the abundance of raw material? Well, glass is made mostly of silica which is in abundant supply, that's true. But the cost of manufacture—especially fuel and other materials has increased significantly over time.

Or could be our industry is intent on eating its own flesh in a cannibalistic frenzy with little or no thought of the future?

If the glass industry had written that little orange book I enjoyed so much in college, the title would most probably have been "How to Cry with Statistics."



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