the 1986 revision attempted to retain all the strengths of the earlier revisions while eliminating the weaknesses.this was no easy task. to continue to provide a measure of general mental ability,the authors of the 1986 revision decided to retain the wide variety of content and task characteristics of earlier version. however, to avoid having this wide content unevenly distributed across age groups,the age scale format was eliminated. in place of the age scale,items with the same content were placed together into any one of 15 separate tests. for example, all vocabulary items were placed together in one test: all matrix items placed together in a second.(see table 10-3 for a list of tests.)