Many factors

1. Macleans has a rich history of success in the chemistry olympiad so students are more motivated to follow the steps of past students and aim high as we know it’s possible.
2. Macleans students are usually accelerated in their science studies a year earlier than usual which means that students get involved in olympiad in the end of year 11 which means that interschool competition (both inside a year and between different year levels) for limited places in the olympiad is tough which means that only the very best Macleans students actually make it to camp. (Camp is limited to 4 students per school). Competition makes us work harder which means that we’re usually better than students from other school. Also some students would have competed in the olympiad for multiple years, giving them an advantage.
3. Some past students help current students which gives an extra edge compared to students from other schools.
4. Macleans is very focused on acing NZQA Scholarship Exams starting from around year 11 these days which nurtures problem-solving skills that are vital for excelling in Olympiad.
5. Based on historical data, most would agree Macleans is the top academic school in New Zealand with the smartest students (Westlake, AGS, and Kings arn’t even close ) So, it’s no suprise we wreck everyone.