Batch cycle-001. Model 0.1.0, graph 0.2.0, parameters 0.1.0. 100 simulations, seeds 1 to 100; probes on 20. Every figure is a distribution over simulations of a structural model with seed parameter values; it shows what the model implies under these settings, not what will happen. Other nations are frozen at their 2026 ratings. No reconstructed historical data is used in this experiment.
Headline
United Kingdom played 20 rounds from 2026 under the hold method, with stochastic events, 100 times. Its capability index moved from 16.45 to a median of 16.14 (−0.31), with 90 per cent of simulations between 15.11 and 17.29 [experiment_objectives].
Starting position
In 2026 the nation ranks 3 on the index against the frozen field, holds 2 of nine domains at Tier 1 and has a tier rank of 5. Its base income is 951 credits a year, calibrated so that its 2026 position is affordable with headroom for investment.
What was decided
No actions were taken: the method holds, so income pays maintenance and the rest is carried over.
What the world did
A median simulation saw 2 shocks and 1 upside events. The most damaging per firing were S01 (26 firings in 22 simulations, −25.4 points each); S08 (33 firings in 29 simulations, −25.3 points each); S03 (33 firings in 31 simulations, −24.7 points each) [experiment_shocks]. Upside events fired 139 times across all simulations [experiment_shocks].
The groups that lost most to shocks, per simulation: Fiscal Capacity & Public Finance −1.09; Economic Leverage & Dependence −1.05; Trade Facilitation & Logistics −0.98; Digital & Services Trade −0.94 [experiment_shock_damage_by_group].
The edges that carried most change through the graph, per simulation: Fiscal Capacity & Public Finance to Social Infrastructure (−0.12 points); Economic Output & Productivity to Fiscal Capacity & Public Finance (−0.07 points); Fiscal Capacity & Public Finance to Force Generation & Mobilisation (−0.07 points) [experiment_propagation_by_edge].
Where it ended
At 2046 the median rank is 5 (5th to 95th percentile 2 to 10), the median count of Tier 1 domains 1 (0 to 5) and the median tier rank 10; the resilient score, the mean score sum over simulations, is 1,174 [experiment_objectives].
Tier 1 probability changed most in: financial strength (0 to 32 per cent of simulations); governance and integrity (100 to 75 per cent of simulations); human capital (0 to 34 per cent of simulations); production and innovation (100 to 41 per cent of simulations) [experiment_tiers_by_round].
Why
Without shocks the index ends +0.866 higher on average, so the shocks cost about 0.866 index points [experiment_probe_attribution].
Holding instead of following this method changes the index by 0.000: that is the method's worth against doing nothing [experiment_probe_attribution].
Removing the largest shock of a simulation raises the index by +0.418 on average [experiment_probe_attribution].
The replay probe reproduces the simulations exactly (index change 0.000000), so the attributions are clean [experiment_probe_attribution].
Surprises
tier_jump (warn): largest gain in one domain within five years: 4 tiers (8 simulations above 2).
retired_words (warn): e3-gbr-hold/report.md: 'simulations' 1 time(s), first near line 37; use 'simulations'.
The simulation furthest from the median (seed 33) ends −2.11 from it, with 7 shocks and 0 upside events [experiment_outlier_simulations].
Comparison
This is the baseline (hold) experiment, or there is none for this nation in the batch.
No backcast comparison: this experiment does not start from a historical position [experiment_against_history].