Monetary-policy tuning

Use monetary_policy_adjustments to specify transitions for starting INTX values. The generated values are written to a CSV file in the model’s data/ directory.

A regional override has one of two forms: a complete transition, or exactly {exclude: true} to exclude that region from INTX tuning. Exclusions are available in the unreleased modified Python G-Cubed 5.0.2.0 source that implements this feature. The YAML retains schema_version: 1; an older installed package may reject the new override form.

One default transition

baseline_tuning:
  monetary_policy_adjustments:
    projections_file_name: baseline_INTX_projections.csv
    defaults:
      start_year: 2023
      end_year: 2030
      annual_decay_percent: 50.0

Region	Effective setting
USA	2023–2030 transition; 50 per cent annual decay
CHN	2023–2030 transition; 50 per cent annual decay
Any other region	The same default transition

When starting_intx_value is omitted, G-Cubed calculates the equation-consistent starting value.

Exclude one region from the default

baseline_tuning:
  monetary_policy_adjustments:
    projections_file_name: baseline_INTX_projections.csv
    defaults:
      start_year: 2023
      end_year: 2030
      annual_decay_percent: 50.0
    region_overrides:
      OIL:
        exclude: true

Region	Effective setting
OIL	No starting-value calculation or generated INTX transition
USA	Default 2023–2030 transition; 50 per cent annual decay
Any other unlisted region	The same default transition

This recipe uses the exact region code from the selected model. The 22U build 200 aggregation contains OIL; other aggregations may contain MEN instead. They are different model-region identifiers, not aliases. The tuner validates every override key against the model’s regions before writing files. It does not detect exchange-rate pegs or choose exclusions automatically.

Only the YAML boolean true is valid for exclude. false, null, quoted "true" and 1 are invalid. An exclusion cannot contain transition fields, including starting_intx_value. Remove the regional entry to restore default inheritance, or replace it with a complete transition to tune that region. There is no separate excluded_regions field.

Exclusion preserves the existing database INTX value; it does not zero or restore a value fitted by an earlier run. When apply has surviving transitions, it rewrites the managed transition CSV with those regions only, removing any previous excluded-region rows. summary omits excluded regions from its decisions and diagnostics while preserving model inputs. Handle any previously fitted database values deliberately before rebuilding a baseline.

Override one region completely

baseline_tuning:
  monetary_policy_adjustments:
    projections_file_name: baseline_INTX_projections.csv
    defaults:
      start_year: 2023
      end_year: 2030
      annual_decay_percent: 50.0
    region_overrides:
      JPN:
        start_year: 2024
        end_year: 2034
        annual_decay_percent: 25.0
        starting_intx_value: 0.5

Region	Effective setting
JPN	2024–2034, 25 per cent decay, starting value 0.5
USA	Default 2023–2030 transition
Any other unlisted region	Default 2023–2030 transition

Several overrides and recalculated starts

baseline_tuning:
  monetary_policy_adjustments:
    projections_file_name: baseline_INTX_projections.csv
    defaults:
      start_year: 2023
      end_year: 2030
      annual_decay_percent: 50.0
      starting_intx_value: null
    region_overrides:
      USA:
        start_year: 2023
        end_year: 2028
        annual_decay_percent: 60.0
      CHN:
        start_year: 2025
        end_year: 2035
        annual_decay_percent: 20.0
        starting_intx_value: -0.25

null and omission both request the equation-consistent starting value. Each regional transition still supplies all three required transition fields.

Tune named regions only

baseline_tuning:
  monetary_policy_adjustments:
    projections_file_name: baseline_INTX_projections.csv
    region_overrides:
      USA:
        start_year: 2023
        end_year: 2030
        annual_decay_percent: 50.0

Unlisted regions have no configured INTX transition.

Exclusions also work without defaults. For example, adding OIL: {exclude: true} beside the complete USA transition above keeps OIL excluded and tunes only USA, provided both codes belong to the selected model.

No effective transitions

baseline_tuning:
  monetary_policy_adjustments:
    projections_file_name: baseline_INTX_projections.csv
    region_overrides:
      OIL:
        exclude: true

With no default or complete regional transition, summary and apply report no configured operations, return no decisions and write no model inputs or diagnostics. The same applies when every default transition is excluded. Existing files remain untouched, including previous managed transition rows. Unknown region codes still fail validation before this no-op. disabled continues to return without reading or writing tuning inputs.

Invalid partial override

region_overrides:
  JPN:
    end_year: 2034

This is invalid. A regional transition cannot inherit start_year or annual_decay_percent from defaults. Supply the complete transition or the separate exclusion form; combining the two forms is invalid. Exclusions apply only to monetary regional overrides, not monetary defaults or real-interest-rate tuning.

Validation and errors