Ethiopia-specific calibration sources

[SeaCelo]

Layered on the structural PR. Addresses data sourcing problems specific to Ethiopia.

alpha_T — the IMF GFS G27_T series is zero for Ethiopia, which is a reporting gap not a real zero. The default value of 0.0035 in ogeth_default_parameters.json is derived from the IMF program target for government cash contributions to PSNP/UPSNP in FY2024/25 (51.4 billion birr against nominal GDP of 14,856 billion birr). Users can update this directly in the defaults JSON as better data becomes available.

alpha_G — IMF GFS S1311B understates government consumption by ~4pp because Ethiopia's regional states do substantial spending not captured in the budgetary central government sector. Switches to World Bank NE.CON.GOVT.ZS (general government final consumption, % of GDP) using the same WB API call already made for GDP growth.

g_y_annual — trims the growth averaging window to 2006 onward, excluding the pre-reform period.

r_gov_shift / r_gov_scale — removed from live calibration. The OLS calculation uses only hardcoded inputs from Li et al. (2021) and always produces the same result, so running it at calibration time adds no value. The values are already in ogeth_default_parameters.json and the documentation preserves the methodology with a reproducible code snippet.

Documentation (macro.md, exogenous_parameters.md)

• Explains the PSNP-based alpha_T sourcing with calculation details
• Documents the switch to NE.CON.GOVT.ZS for alpha_G and why
• Updates all changed parameter values in the exogenous parameters table
• Adds reproducible Python snippet for the r_gov_shift/r_gov_scale one-time calculation
• Updates debt and foreign-debt sourcing notes with FY2023/24 MoF references