Does the minimum value of a distribution influence the efficacy of a transformation?
For researchers with a strong mathematical or statistical background, the points made in this section are self-evident. However, over the years many of my students and colleagues have helped me to realize that to many researchers this point is not self-evident; further, it is not explicitly discussed in many statistical texts. First, note that adding a constant to a variable changes only the mean, not the standard deviation or variance, skew, or kurtosis. However, the size of the constant and the place on the number line that the constant moves the distribution to can influence the effect of any subsequent data transformations. As alluded to above, it is my opinion that researchers seeking to utilize any of the above-mentioned data transformations should first move the distribution so its leftmost point (minimum value) is anchored at 1.0. This is due to the differential effects of the transformations across the number line. All three transformations will have the greatest effect if the
