Holland developed the hexagon, known by counselors worldwide, in the 1960s when he was ACT Vice President for Research. But the hexagon has only six types of interests and occupations. Interest inventories have been around for a long time. Items have been carefully chosen to assess basic interests while minimizing the effects of sex-role connotations. Ability tests have been around for a long time.
Occupations differ on a wide range of abilities.
Thus, a comprehensive search for occupations requires a comprehensive assessment of abilities. ACT has conducted five large-scale studies comparing IWRA's validity for career exploration to those of test batteries. First, IWRA addresses a wide range of work-relevant abilities. Second, IWRA abilities are broadly defined in everyday terms. Third, test-estimates of ability are often based on only a small sample of behavior collected in just a few minutes.