ABSTRACT
Behavioral scientists are interested in answering three basic questions when examining the relationships between variables (Kirk, 2001). First, is an observed result real or should it be attributed to chance (i.e., statistical significance)? Second, if the result is real, how large is it (i.e., effect size)? Third, is the result large enough to be meaningful and useful (i.e., clinical or practical significance)? In this chapter, we treat clinical significance as equivalent to practical significance.
