“There are three kinds of lies: lies, damned lies and statistics.” (Benjamin Disraeli or not, sic!)
In his introduction to Reading Educational Research – How to Avoid Getting Statistically Snookered, Gerald W. Bracey states, “Misleading statistics abound. “ His entire book is an illustration of this claim, starting from the very chapter (Data, Their Uses and Their Abuses) to the final part (Testing: A Major Source of Data – and Maybe Child Abuse).
*As a side note, I loved reading in the Foreword about his struggle to expose statistics abuse for years as he demystified the politics behind many U.S. educational programs, institutions and policies (No Child Left Behind, NAEP – National Assessment for Educational Progress and more). At the time of writing this book he was losing a part-time job at George Mason University because, as Jay Mathew remarked, “The school couldn’t take the heat that often follows Bracey in his scholarly travels.” – in other words, he was too direct in his approach to truth.
The book is full of examples that support the 32 Principles of Data Interpretation and guides the reader to a deeper understanding of how data is collected, presented and used. I will only selectively refer to some of them as I cannot obviously make a summary in a single blog post.
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Principle 1: Do the arithmetic
Failure in doing the math occurs mostly in examples that track changes in data over time.