請教各位大俠，關於same or similar occupational category

最近看了Ron Gotcher關於same or similar occupational category的分析, 不知道他說的是否有道理？請各位大俠分析下, 或者哪位有經驗的能談談?

http://imminfo.com/News/Newsletter/2010-07/Same-or-similar-occupational-classification.html

這裏是我copy的其中一段.
The O*Net also groups occupations by “Career Clusters.” This appears to be a narrow grouping. The definition of this category is: “Career Clusters contain occupations in the same field of work that require similar skills.” Note that the emphasis here is “same field of work” – not “same or similar.” I think that we can safely say that all occupations within with the same “career cluster” qualify as “the same occupational classification.”

http://online.onetcenter.org/find/career?c=15&g=Go

也就是說隻要是同一個career cluster裏的就qualify “the same occupational classification.”? 比如說electical engineer 和 Statisticians 都屬於Science, Technology, Engineering and Mathematics， 那麽他們就是“the same occupational classification.”， 符合AC21的要求?

不知道我的理解對不對?