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IBO 2025 Results Analysis

IBO 2025
Quezon City, Philippines -- by the numbers
298
Competitors
81
Countries
4
Practical Labs
2
Theory Papers

Final Medal Tally

How the medals fell

Gold
30
Silver
60
Bronze
89
Merit
30

The Odds

What it actually took to medal in 2025

Top of the Podium
Tianran Ma
China · Final score 98.48
1st
Started the exams
298
Earned any award (G+S+B+M)
209
Medaled (G+S+B)
179
Reached Gold or Silver
90
Gold medal
30

Only 1 in 10 competitors (10.1%) walked away with Gold. The 60.1% medal rate was moderate by IBO standards, and the gaps between tiers were the tightest in recent memory.


Medal Cutoffs

Where the lines were actually drawn

Final score range needed to earn each award

Gold
82.21 -- 98.48
Silver
71.00 -- 81.83
Bronze
56.96 -- 70.72
Merit
53.09 -- 56.75
Record-tight margins

The Gold cutoff (82.21) sat just 0.38 points above the best Silver score (81.83). Silver-Bronze was even tighter at 0.28, and Bronze-Merit was 0.21. These are among the slimmest gaps in IBO history: a single extra mark on one station would have changed medal colors for dozens of competitors.


By the Numbers

How hard was each station, really?

Average points earned vs. each lab's own maximum

82%
Cell & Molecular Biology
46.8 / 57.0 pts
74%
Ecology & Systematics
51.6 / 70.0 pts
81%
Biomedical Science
41.1 / 51.0 pts
81%
Microbiology
77.4 / 96.0 pts
Hardest to score on

Ecology & Systematics was the toughest station: competitors captured just 74% of its 70 available points. It also had the lowest correlation with final rank (r = 0.66), making it the most "unpredictable" station where strong students sometimes stumbled.


Theory was king (again)

Theory total (Papers 1 + 2 combined) correlated at r = 0.94 with final score. Theory 1 averaged 78% attainment, Theory 2 averaged 72%. The combined theory score averaged 57.2 out of 76.4 maximum (75%).


Team Standings

Top 15 delegations by medal count

#DelegationGSBAvg Score
1China40094.8
2Singapore40088.8
3United States31084.8
4Iran31083.1
5India22082.6
6Turkiye22079.4
7Chinese Taipei13081.4
8Thailand13077.1
9Vietnam12179.5
10South Korea12179.3
11Poland12176.3
12Germany12175.4
13Israel12173.9
14Australia11274.0
15Japan04075.3
Gold sweeps

China and Singapore are the only delegations where all 4 members won Gold. China's team averaged 94.8, the highest of any delegation by a margin of 6 points. Singapore's 4-Gold showing is a significant rise from IBO 2024 (where they earned 2G 2S).


Theory vs. Practical

Some teams live on paper, others in the lab

Average gap between theory z-score and practical z-score, by country (teams of 4 only)

Stronger in Theory

Vietnam
+1.08
China
+0.79
United States
+0.76
Iran
+0.63

Stronger in Practicals

North Macedonia
-0.69
Croatia
-0.66
Portugal
-0.58
France
-0.55
Reading this

Vietnam had the largest team-level theory advantage in 2025, finishing 1.08 standard deviations higher on theory than on practical. China and the United States followed a similar pattern. On the practical side, North Macedonia and Croatia built their performances disproportionately in the lab.


Curiosities

4 things the official result does not say out loud

01
r = 0.942 and r = 0.942

Theory z-score and practical z-score correlated with final score at exactly the same strength: 0.942. This is a rare perfect balance. In most IBO years, theory dominates. In 2025, if you wanted to predict someone's final rank, theory and practical performance were equally useful.

02
0.21 points

The gap between the last Bronze and the first Merit was just 0.21 points. In a 98.48-point competition, that is 0.2% of the winner's score. A single miscounted colony on a microbiology plate would have changed the outcome.

03
Ecology was the wildcard

Ecology & Systematics had the lowest correlation with final rank (r = 0.66) of any component. Strong students sometimes bombed it; weaker students sometimes aced it. It was the most unpredictable station, with just 74% average attainment. If you studied for this station specifically, you had a statistical edge others did not.

04
Zhiyuan Wu: +1.52 theory-practical gap

China's 3rd-place finisher had the largest individual theory-over-practical gap in the entire field. His theory z-score was 1.52 standard deviations above his own practical average, yet he still finished 3rd overall (score 94.9). Pure theory dominance at the very top of the field.


For 2026 Hopefuls

What the data says to train next

1

Theory and practical matter equally

Both correlated at r = 0.94 with final score. Do not neglect either. A balanced study plan that alternates between written problems and hands-on lab work is the statistical optimum.

2

Ecology & Systematics was the differentiator

At 74% average attainment, it was the station where most competitors left points. Spending targeted time on field ecology, species identification, and cladistics gives you the most room to gain where others lose.

3

The margins are vanishingly small

Merit to Bronze: 0.21 points. A steadier finish across all four labs is what closes this gap.

Bronze to Silver: 0.28 points. Focus on partial-credit marks on the theory paper before hunting new topics.

Silver to Gold: 0.38 points. At this level, it is about avoiding any single bad station.

4

Cell & Molecular Biology was the easiest points

With 82% average attainment, CMB was the most accessible station. Make sure you are not leaving free points here. Then invest extra time where the field struggles: Ecology (74%) and Theory Paper 2 (72%).


Independent analysis of the official IBO 2025 final results PDF. Not an official IBO publication.