
Tukey's Bulging Rule for Straightening Data Bruce Ratner, Ph.D. "A very effective and simple technique for straightening data is reexpressing the variables, which uses Tukey’s Ladder of Powers and the Bulging Rule. Before presenting the details of the technique, it is worth discussing the importance of straightline relationships or straight data."  Ratner, B., Statistical Modeling and Analysis for Database Marketing: Effective Techniques for Mining Big Data, CRC Press, Boca Raton, 2006. The following is an excerpt from Chapter 3, pages 39 41. 3.5.2 Bulging Rule The Bulging Rule states the following:
Reexpressing is an important, yet fallible part of EDA detective work. While it will typically result in straightening the data, it might result in a deterioration of information. Here is why: reexpression (going down too far) has the potential to squeeze the data so much that its values become indistinguishable, resulting in a loss of information. Expansion (going up too far) can potentially pull apart the data so much that the new farapart values lie within an artificial range, resulting in a spurious gain of information. ... An excellent realcase illustration follows (pages 41 50 in the book). Related Articles: 0. Tukey's Bulging Rule: What to Do When It Fails 1. The Correlation Coefficient: Definition 2. When Data Are Not Straight 3. Data Mining and Its Applications 1 800 DM STAT1, or email at br@dmstat1.com. 
