The 2026 tournament added 16 teams and a 12-group stage. Comparing group-stage upset index (−log₂ of the model's probability of each result) for 2026 against the pooled 2002–2022 group stages — purely descriptive, no causal claim. ← all-time shocks
The 48-team group stage produced +65% more big shocks (upset index ≥3.0) than 2002–2022 — 9.7% vs 5.9% — though the overall surprise distribution was statistically indistinguishable (Mann–Whitney p=0.18).
Cumulative share of group-stage matches below each upset index. A curve to the RIGHT = more surprising matches.
| Group stage | n | median | mean | ≥3.0 | ≥4.61 |
|---|---|---|---|---|---|
| 2026 (48-team) | 72 | 0.94 | 1.31 | 9.7% | 0.0% |
| 2002–2022 pooled | 288 | 1.23 | 1.44 | 5.9% | 1.7% |
Mann–Whitney U=9310, z=-1.34, p=0.180. The bigger field delivered a higher rate of large shocks, but 2026's typical (median) group match was actually calmer and it produced no beyond-resolution result — so the distributions as a whole are not statistically distinguishable.