Achievements in a talent area (eg. olympiads, NSG rankings, competitions, position, etc) form one component of our evaluation of each student. They are useful as students who are talented in a particular area would usually have some participation beyond the normal classroom/cca.
If your son does not have any of these achievements, we still welcome him to apply if he really has talent / abilities in that domain as evidenced in other ways (whether it is through his results or other activities).