I am looking at St. Margaret Sec Sch.Quote from SMSS website:For Secondary 1 Admission Qns: What is the cut-off point for affiliated / non-affiliated students?Ans: For affiliated students, there is no cut-off point. So long as St. Margaret’s is the first choice, the student will get a place. For non-affiliated students, the cut-off was 240 in 2008.Qns: Does St. Margaret’s have an affiliated primary school?Ans: Yes. St. Margaret’s Primary SchoolQns: Are other Anglican schools affiliated?Ans: Yes. St. Margaret’s is also affiliated to St. Andrew’s Junior College.Qns: What are the chances for a non-affiliated student gaining admission into St. Margaret’s?Ans: A student would enjoy a fair chance if she scores above 240 and puts St. Margaret’s as a 1st choice.Qns: What is the percentage of SMPS students in St. Margaret’s?Ans: More than 50% of our students come from SMPS. There will always be places for students from other schools who meet the qualifying cut-off point.UnquoteSo, based on above, SMSS reserve at least 50% for internal students. But as to how to determine cut off for non affialiated students, it is not explicit. I guess the sch & MOE do have certain parameters that we do not know.