This article provides a comprehensive review of research regarding five types of validity for each of four major tests used to measure emotional intelligence (EI). It culls and synthesizes information scattered among a host of articles in academic journals, technical reports, chapters, and books, as well as unpublished papers and manuscripts. It enables human resource development professionals and researchers to determine the absolute and incremental value they are likely to derive by using any one of the tests to assess and develop emotional intelligence among managers and employees.Emotional intelligence (EI) is growing into a multimillion dollar training industry (Kunnanatt, 2004;Adkins, 2004). Because the major vendors of training use various means of measuring it, human resource development (HRD) professionals are forced to consider which index to choose for developmental purposes-that is, which index offers added value above and beyond existing tests (personality and intelligence), is conceptually sound, and is likely to have more face validity than another from the vantage point of managers and employees. Moreover, development professionals must consider which index has more predictive power than the others in explaining work-related phenomena and can be used to measure EI among individuals with markedly different demographic attributes operating in different contexts (for example, Thai versus Mexican American managers in retail sales versus health care executives). In sum, the task facing HRD professionals and researchers is to determine which test has more construct (convergent and divergent), content, face, predictive, and external validity than others.HRD professionals stand much to gain from efforts to identify an effective EI index for a wide range of developmental applications in the workplace. example, EI indexes have been used for training and development programming, organizational development initiatives, and career development planning. Assessments of EI dimensions have facilitated training and development modules for customer service skills, conflict management strategies, and stress management programs (Rozell, Pettijohn, & Parker, 2004;Cherniss, 2000). Similarly, HRD professionals have used EI measures as components in individual development plans (Cummings & Worley, 2005;Kunnanatt, 2004), organizationwide competency models (Gowing, O'Leary, Brienza, Cavallo, & Crain, 2005), and executive coaching interventions (Peterson, 1996). At the group and organization level of application, EI indexes have critical implications for team building and enhancing team effectiveness (Druskat & Wolff, 2001) and for assessing capacity for organizational change and performance in various structural arrangements (Sy & Cote, 2004). However, the effective application of any EI index to organizational applications requires a thorough assessment of the measure' s psychometric qualities and appropriate fit for the particular intervention. Unfortunately, no comprehensive assessment of the major EI measures and their...