GravityGE.jl

A Julia package for gravity models in international trade with general equilibrium effects.

Overview

GravityGE.jl implements gravity models for analyzing bilateral trade flows with general equilibrium effects. The package provides tools for:

  • Bilateral Trade Analysis: Analyze trade flows between countries/regions
  • General Equilibrium Effects: Account for wage and price adjustments
  • Counterfactual Analysis: Simulate productivity and trade cost shocks
  • Welfare Analysis: Compute welfare effects of trade policy changes

Key Features

  • Validated Data Structures: Comprehensive validation of trade flow data
  • Flexible Shock Analysis: Support for productivity (a_hat) and trade cost (beta_hat) shocks
  • Convergence Guarantees: Robust numerical methods with configurable tolerance
  • Policy Simulation: Tools for analyzing trade agreements and policy reforms

Installation

using Pkg
Pkg.add(url="https://github.com/noejn2/GravityGE.jl")

Quick Start

using GravityGE
using DataFrames

# Create bilateral trade data
trade_data = DataFrame(
    origin = ["USA", "USA", "CAN", "CAN"],
    destination = ["USA", "CAN", "USA", "CAN"],
    value = [500.0, 100.0, 80.0, 200.0]
)

# Run gravity GE analysis
theta_value=4.0 # Trade elasticity assumed to be 4.0
result = gravityGE(trade_data; theta=theta_value)

# Access welfare effects (all ones since no simulation shocked is assumed)
println("Welfare changes: ", result[:new_welfare])

# Run gravity GE analysis assuming trade costs between USA and CAN increased by 50%
trade_data.bitrade .= -1*theta_value*log(1.5)
trade.bitrade[trade.origin == trade.destination ] .= 0
result = gravityGE(trade_data; theta=theta_value, beta_hat_name="bitrade")
println("Welfare changes: ", result[:new_welfare])

# Run gravity GE analysis assuming trade costs between USA and CAN increased by 50% and productivity in the USA and CAN falls
trade_data.prod = 0.5
result = gravityGE(trade_data; theta=theta_value, beta_hat_name="bitrade", a_hat_name="prod")
println("Welfare changes: ", result[:new_welfare])

Package Structure

The package is organized around several key components:

Citation

If you use GravityGE.jl in your research, please cite:

@software{gravityge_jl,
  author = {Nava, Noé J.},
  title = {GravityGE.jl: A Julia Package for Gravity Models with General Equilibrium Effects},
  url = {https://github.com/noejn2/GravityGE.jl},
  version = {0.1.0},
  year = {2025}
}

License

This package is licensed under the MIT License.

Contributing

Contributions are welcome! Please open an issue or submit a pull request.