I was a coordinator for last year’s IMO 2024 and this year’s IMO 2025.Before, I was a coordinator for some virtual IMO during the pandemic too, which is much less fun. And from 2017-2019 I was an observer for the USA. Here’s some thoughts about that, contrasting my IMO 2019 post.

What is coordination?

For those of you that don’t know, coordination is the grading process for IMO. As I describe it in my FAQ:

Basically, the outline of the idea is: before the exam, a marking scheme (rubric) is set for each problem, to cover the typical cases of what progress will be worth what points. Then, the leaders of each country get to see the solutions of their country’s students, while there is a number of coordinators from the IMO host country for each problem. Both the coordinators and the leaders read …

Here is my commentary for the 2019 International Math Olympiad, consisting of pictures and some political statements about the problem.

Summary

This year’s USA delegation consisted of leader Po-Shen Loh and deputy leader Yang Liu. The USA scored 227 points, tying for first place with China. For context, that is missing a total of four problems across all students, which is actually kind of insane. All six students got gold medals, and two have perfect scores.

1. Vincent Huang 7 7 3 7 7 7
2. Luke Robitaille 7 6 2 7 7 6
3. Colin Shanmo Tang 7 7 7 7 7 7
4. Edward Wan 7 6 0 7 7 7
5. Brandon Wang 7 7 7 7 7 1
6. Daniel Zhu 7 7 7 7 7 7

Korea was 3rd place with 226 points, just one point shy of first, but way ahead of the 4th place score (with 187 points …