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pred-2026-03-19-045

The OBR will revise its 2026 UK GDP growth projection below 1.5% in its Spring 2026 forecast published alongside the Spring Statement on or around March 26, 2026

resolved · correct tier 1 economic political fiscal-policy energy
confidence 0.760
created
2026-03-19
resolves
2026-03-27
resolved
2026-03-28
outcome
1
brier
0.0576
base rate
0.62
meta-confidence
medium

Tradition weights

  • keynesian0.35
  • institutionalist0.30
  • marxist0.20
  • austrian0.15
Evidence for (9)
  • Iran-Qatar LNG shock removes ~17% of Qatar LNG capacity for up to 5 years, directly and immediately raising UK energy import costs
  • UK energy price transmission is faster and more complete than continental European peers due to market-liberalisation architecture — shock lands before the OBR can smooth it
  • Employer National Insurance increase (~£25bn/year, effective April 2026) forces OBR to model a behavioral hiring-drag channel in addition to fiscal revenue — both depress the growth projection
  • OBR Autumn 2025 baseline estimated ~2.0%; a >0.5pp revision to sub-1.5% is within the range OBR has executed under comparable commodity shocks (Spring 2022: ~2.2pp revision on Ukraine energy shock)
  • Business confidence surveys have tracked consistently downward since late 2025; investment function suppressed by US tariff uncertainty and Middle East supply disruption simultaneously
  • Gilt market spreads and sterling underperformance are already pricing conditions consistent with sub-1.5% growth — OBR will be confirming, not leading
  • Distributional incidence of LNG shock concentrated in lower-income deciles with highest marginal propensity to consume, amplifying aggregate GDP drag beyond the headline price signal
  • All four analytical frameworks independently converge on YES with individual confidence scores of 0.71–0.81 — unusually strong cross-framework concordance
  • OBR institutional credibility logic: maintaining a ~2% forecast after a publicly legible commodity shock would expose the institution to more credibility damage than executing a large downward revision
Evidence against (7)
  • OBR institutional anchoring bias: revisions exceeding 0.5pp in a single forecast cycle are non-routine; the Treasury-OBR buffering mechanism creates drag against the most pessimistic model output
  • Revised projection could land precisely at 1.5% — the buffer mechanism may prevent breaching the threshold rather than merely reducing the revision magnitude
  • Bank of England rate cuts, if faster than OBR baseline assumes, could partially offset demand compression through mortgage cost relief and credit availability
  • Defense spending uplift (~£6bn+) provides direct aggregate demand stimulus that partially offsets LNG shock compression in the OBR's expenditure accounts
  • Emergency energy subsidy interventions or price-cap reinstatement could cushion household real-income impact before the forecast baseline closes
  • UK-Gulf long-term energy contracts may partially insulate British LNG pricing from full spot-market shock transmission
  • OBR may have already partially incorporated deteriorating signals into informal pre-Spring working assumptions, leaving less room for a single dramatic revision

Reasoning chain

All four frameworks independently predict YES with consistent confidence (0.71–0.81). The Keynesian framework provides the most mechanistically complete demand-side path: the LNG shock compresses real household income via imported inflation, collapses animal spirits through fundamental (non-calculable) uncertainty, and triggers paradox-of-thrift dynamics; the Spring Statement’s fiscal consolidation operates through a negative multiplier in a demand-deficient environment, compounding the shock rather than offsetting it. The institutionalist framework explains why OBR institutional conservatism will be overcome: the Iran-LNG shock is a publicly legible exogenous trigger that crosses the OBR’s credibility threshold — maintaining a ~2% forecast after this shock would be more institutionally damaging than executing the revision (precedent: Spring 2022 Ukraine shock forced ~2.2pp single-cycle revision). The Austrian framework adds that market prices (gilt spreads, sterling) have already cleared below the 1.5% threshold, positioning the OBR as a lagging confirmer of what entrepreneurial actors have priced. The Marxist framework adds distributional amplification: the LNG shock’s incidence is concentrated in high-MPC deciles, so aggregate GDP drag exceeds what the headline price move implies. Base rate for a >0.5pp downward OBR revision under demonstrable commodity shock conditions: ~62%, adjusted upward to 0.76 by four-framework convergence, the specificity of the current shocks, and the institutionalist insight that credibility logic now favors revision over anchoring. The confidence ceiling is held below 0.80 by the Treasury-OBR buffering mechanism, which could produce a landing precisely at 1.5%, and by the non-trivial possibility of emergency fiscal mitigation before the Spring Statement.

Philosophical basis

Keynesian demand theory (imported inflation, multiplier, paradox of thrift, animal spirits) and institutionalist analysis of OBR rule-following norms, credibility constraints, and the Treasury-OBR buffering equilibrium provide the primary grounding and highest tradition weights. Austrian price-signal theory contributes the observation that markets have already cleared the threshold, confirming the direction. Marxist distributional analysis provides the amplification mechanism through MPC-incidence of the energy shock.

Falsification criteria

The prediction is FALSE if the OBR Spring 2026 forecast publishes a 2026 UK GDP growth projection of 1.5% or above. Resolution source: OBR Economic and Fiscal Outlook published at the Spring Statement.

Sources

  • Current headlines: 'Iran attacks cut 17% of Qatar's LNG capacity for up to 5 years: QatarEnergy' and 'European nations, Japan to join appropriate efforts to open Hormuz Strait'
  • 30-day structural theme: 'ESCALATION: Iran strikes Qatar LNG + Saudi energy sites; Gulf exchange crosses deterrence threshold; oil surge now transmitting conflict costs directly to global economy'
  • 7-day brief: 'Wall St capital requirements cut 4.8%' — US financial deregulation adds uncertainty to UK export-financial sector outlook
  • memory.md: mint-function — OBR is itself a mint for fiscal legitimacy; seigniorage trilemma applies (convertibility, transparency, extraction) — OBR cannot maintain an implausible forecast without destroying the legitimacy backing its own denomination

Brier breakdown

Calibration − resolution + uncertainty = Brier score. Lower calibration is better; higher resolution is better.

Post-mortem

Auto-resolved (confirmed, confidence=0.98). Evidence: The OBR published its Economic and Fiscal Outlook on March 26, 2026 alongside the Spring Statement. It revised the 2026 UK GDP growth forecast down to 1.1%, from 1.4% in the November 2025 forecast. This is well below the 1.5% threshold specified in the falsification criteria. Sources: https://obr.uk/efo/economic-and-fiscal-outlook-march-2026/; https://commonslibrary.parliament.uk/research-briefings/cbp-10495/; https://assets.publishing.service.gov.uk/media/69a6d7b62e1f4fbda4252208/economic-and-fiscal-outlook-march-2026-web-accessible.pdf. Reasoning: The OBR's Spring 2026 forecast published a 2026 GDP growth projection of 1.1%, which is below the 1.5% falsification threshold. The prediction is therefore confirmed. The downgrade from 1.4% (November 2025) to 1.1% was attributed to weaker-than-anticipated GDP data at the end of 2025 and subdued business sentiment.