In general, universities in singapore tend to follow the british system of admissions more closely. There is a special emphasis on A/O level results above everything else, so other things like CCA/SAT/teacher recommendations don’t come into play that much.
If you are looking specifically at the com sci / comp eng (ie. hard science majors) in local institutions, then you’re pretty much required to take higher maths, chem and physics and get good A level grades in them. As for cca records and other accomplishments, they wouldn’t make that big of a difference unless the achievements at hand are really impressive to admission committees (eg. winning a gold at the international biology olympiad, setting a record at the SEA games).
Chances are, for the average to above-average applicant, cca & other outside achievements would be limited to participating in a school club, taking an officer position, and winning some minor in-school awards. While these things are definitely not “detrimental,” they wouldn’t sway an admissions vote from “reject” to “accept.” At most, they would boost an applicant’s chances a little if there’s a borderline situation (ie. missing the cutoff admissions index score by 1-5 pts).
However, with American universities, you have a totally different story. With much broader selection criteria covered in their applications, the applicant has to report not only his/her A-level scores, but also SAT results, extracurricular activities, leadership positions, awards and certificates from competitions, and also submit essays and teacher recommendations. For the top universities, admissions interviews lasting about 1-2 hours are also required.
Admission interviews are becoming increasingly common, not only for some majors within the nus/ntu system but also for overseas universities as well. they are more geared towards focusing on the applicant’s personality and social skills, so as long as the student comes across as reasonably well-adjusted, there’s nothing to worry too much about. (for my interviews at least, they were simply one-to-one conversations with a fellow alum, either in his/her office or home; the atmosphere was somewhere in between formal and casual.)
The thing is, although many people might be intimidated by the selection procedure for American schools, it is actually much more flexible than the british system, simply because it takes into account “the whole person” rather than just the applicant’s A-level grade report. It might not necessarily be easier to get into the ivy leagues than oxbridge per se, but having so-so A-level grades wouldn’t kill an applicant’s chances if he/she has something else to offer besides academic exam reports.
As a whole, if you are applying for admissions in the upcoming cycle, or in the one next year, then you should simply concentrate on getting a great set of a-level results. If you have more time than that (eg. 2 years or more), and if you are considering American schools, then you’d probably want to focus on other things like extracurriculars and winning awards, on top of pure schoolwork.
Of course, achievements in cca would not hurt an applicant’s chances within the UK system (they are even expected for US admissions). Having said that, it would still be in the best interest of most students to place main emphasis on schoolwork. Even though winning an award for a national robotics competition may seem like a boost when compared to your child’s group of friends, it would not provide a great advantage when the admission committees are comparing him/her to the entire cohort across singapore. unless the award is extremely prestigious and comes solely via individual achievement (eg. awarded to the top 1% of participants at the national/international level), then it won’t play a huge role, simply due to the limitations within the college admissions process. Admissions officers simply wouldn’t be able to compare one person’s "junior category twelfth place" to another person’s "choreographer of teacher’s day performance" to yet another student’s "assistant director of alumni fundraising."
In the end, the main way that an applicant can differentiate him/herself from others would be through academic achievements, since one more distinction at the A-level, and another 50 points on the SAT can really make a whole lot of difference between accept/reject. As for CCAs, they should be present only to a limited extent, so that the student dedicates only 1 or 2 afternoons to it per week.
If your child is already able to master classwork to the point of complete mastery, advise him/her to start taking part in national and international competitions rather than mere cca clubs. A prize in one of those events would mean a great deal more than juggling 4 or 5 different club activities—the time commitment over four years works out to be virtually the same.
For university admissions, the competitions that are especially well regarded are the international biology olympiad, intl chemistry olympiad, intl mathematics olympiad, and intl physics olympiad.