請教863211,pjiang等大俠

請問你們對於AC21 same or similar occupational classification 有沒有研究? 到底similar的定義是什麽? 我看到 O'net上career cluster, 定義為"Career Clusters contain occupations in the same field of work that require similar skills." 不知道是不是指隻要在同一個cluster 裏的都是 same or similar 的 occupation 呢? 比如這個連接裏的都算?(Science, Technology, Engineering and Mathematics)
http://online.onetcenter.org/find/career?c=15&g=Go