Batch stress-preview. Model 0.2.0, graph 0.2.0, parameters 0.1.1. 100 simulations, seeds 1 to 100; probes on 25. 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 10 rounds from 2026 under the greedy method, with stress events, 100 times. Its capability index moved from 16.45 to a median of 17.22 (+0.77), with 90 per cent of simulations between 16.68 and 17.72 [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 1,094 credits a year, calibrated so that its 2026 position is affordable with headroom for investment.
What was decided
A simulation spent a median of 1,664 credits on actions. The five groups that took most were Lifelong Learning & Reskilling (build, 99 credits, 5.9 per cent); Technical & Vocational Skills (build, 99 credits, 5.9 per cent); Foundational Education (build, 99 credits, 5.9 per cent); Economic Output & Productivity (build, 98 credits, 5.9 per cent); Fiscal Capacity & Public Finance (partner, 68 credits, 4.1 per cent) [experiment_decisions_by_group]. By mode: build 38 per cent, buy 34 per cent, partner 28 per cent [experiment_decisions_by_group]. Concentration of spending (HHI) had a median of 0.038, and the most repeated action appeared in 30 per cent of rounds.
The leading domain by period: rounds 1 to 5, Human Capital; rounds 6 to 10, Critical Technology [experiment_spend_by_period].
The method's chosen action was within 5 per cent of its best alternative in 78 per cent of actions and ahead by more than 25 per cent in 0 per cent [experiment_decision_margins].
What the world did
A median simulation saw 2 shocks and 1 upside events. The most damaging per firing were S02 (100 firings in 100 simulations, −27.8 points each); S01 (19 firings in 16 simulations, −25.7 points each); S03 (17 firings in 16 simulations, −25.7 points each) [experiment_shocks]. Upside events fired 78 times across all simulations [experiment_shocks].
The groups that lost most to shocks, per simulation: Investment Attraction & Projection −1.62; Fiscal Capacity & Public Finance −1.51; Monetary & Currency Capability −1.45; Labour & Employment −1.43 [experiment_shock_damage_by_group].
The edges that carried most change through the graph, per simulation: Economic Output & Productivity to Fiscal Capacity & Public Finance (+0.47 points); Economic Output & Productivity to Development Cooperation & Global Assistance (+0.31 points); Fiscal Capacity & Public Finance to Social Infrastructure (+0.13 points) [experiment_propagation_by_edge].
Where it ended
At 2036 the median rank is 2 (5th to 95th percentile 2 to 2), the median count of Tier 1 domains 7 (4 to 7) and the median tier rank 2; the resilient score, the mean score sum over simulations, is 1,246 [experiment_objectives].
Tier 1 probability changed most in: financial strength (0 to 84 per cent of simulations); governance and integrity (100 to 75 per cent of simulations); human capital (0 to 100 per cent of simulations); information and influence (0 to 97 per cent of simulations); strategic infrastructure (0 to 78 per cent of simulations) [experiment_tiers_by_round].
Why
Without shocks the index ends +0.641 higher on average, so the shocks cost about 0.641 index points [experiment_probe_attribution].
Holding instead of following this method changes the index by −1.299: that is the method's worth against doing nothing [experiment_probe_attribution].
Removing any single one of the five largest actions changes the index by between −0.023 and −0.019, for example 2036 buy Energy Technologies (35 credits) [experiment_probe_attribution]. The largest actions by credits come late, when income is highest, and are rarely the most valuable.
Removing the largest shock of a simulation raises the index by +0.393 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
saturation_high (warn): 90% of simulations end with a group at 20 that did not start there (median 3 groups).
The simulation furthest from the median (seed 86) ends −1.43 from it, with 6 shocks and 1 upside events [experiment_outlier_simulations].
Comparison
Against the hold experiment for the same nation (e5-gbr-s02-hold), the median index is +1.25 points apart, the median rank 2 against 6, and Tier 1 domains 7 against 1 [experiment_against_hold].
No backcast comparison: this experiment does not start from a historical position [experiment_against_history].