According to The EI Edge, written in 2000 by Steven J. Stein and Howard E. Book, research across 30 mostly professional and managerial career fields reveals that anywhere from 47% to 56% of work/life success is the result of EI, with the range being related to job type (Stein & Book, 2000). Even stronger evidence linking EI to the success of leaders within the U.S. was noted by Daniel Goleman, Richard Boyatzis, and Annie McKee in their 2002 book, Primal Leadership.  They found that the most critical leadership skills in the U.S. were linked to emotional intelligence (Goleman, Boyatzis, & McKee, 2002). Their research and the research of others (such as the Hay-McBer consulting firm) suggest that as much as 79% of leadership success in the U.S. results from high EI.  Based on these and other EI studies, it would seem that leaders’ levels of emotional intelligence influence their behaviors, making them more or less successful.

Emotional Intelligence is crucial to success in both work and life in general; it is a part of the biological, evolutionary importance of emotions in human beings.  As Nigel Nicholson, in a Harvard Business Review article, observed, “...for human beings, no less than for any other animal, emotions are the first screen for all information received” (Nicholson, 1998, p. 138).  When a person receives a piece of information, it is automatically assessed from an emotional perspective.  Emotional assessment was necessary for survival when man hunted in small groups, as it initiated “fight-or-flight” responses; things are no different today.  When someone receives information, the older part of the brain still considers a fight-or-flight response.  This phenomenon helps explain why, for example, when a performance appraisal is conducted, even if 99% of the appraisal is positive, the “evaluatee” will fixate upon the negative 1%.  To be successful in any interpersonal activity, one must be aware of one’s own emotions and be able to manage them, just as one must also be aware of the emotions of others and be able to manage any interaction.  EI surveys simply measure the ability to perform these tasks across a wide variety of emotional intelligence skills.

Daniel Goleman, in his landmark Harvard Business Review article, “What Makes a Leader” (HBR Nov. /Dec., 1998, p. 93), shares the following insight into the power of Emotional Intelligence:

"When I calculated the ratio of technical skills, IQ and emotional intelligence (identified in competency models from 188 companies) as ingredients of excellent performance, emotional intelligence was twice as important as the others for jobs at all levels. Moreover, my analysis showed that emotional intelligence played an increasingly important role at the highest levels of the company, where differences in technical skills are of negligible importance."