European Trade Network

Complex-systems analysis of European merchandise trade — centrality, trade communities, and network resilience — built from CEPII BACI open data.

findings, Data & method, executed analysis notebooks, and an interactive community network.

Findings (one line each)

• RQ1. Germany holds the network together (weighted betweenness 0.829); Austria is mid-tier by volume and not a bridge (betweenness = 0).
• RQ2. Three trade blocs emerge (Louvain Q ≈ 0.25) — drawn by geography and intensity, not EU membership.
• RQ3. The complete graph never fragments; on the backbone, targeted hub removal breaks it ~2.6× sooner than random failure, and three economies already hold half the trade value.
• RQ4. Energy (HS-27) is 12% of value but far more concentrated (top 3 ≈ 55% vs 38%) — bridge to austria-energy-analysis.

Reproduce locally

conda env create -f environment.yml
conda activate eu-trade-network
pip install -e .
pre-commit install
nbstripout --install --attributes .gitattributes   # once per clone

# register a Jupyter kernel for this env (optional)
python -m ipykernel install --user --name eu-trade-network

# one-time BACI download → data/raw/  (see data/README.md)
jupyter lab   # run notebooks/01 → 05 top-to-bottom

# preview the site locally (replays _freeze/, no notebook run, no BACI needed)
quarto preview

Publishing

Push to main. That is the whole workflow — .github/workflows/publish.yml renders the site and pushes it to gh-pages, which GitHub Pages serves. Never render or commit onto gh-pages by hand.

CI does not run the notebooks. It replays _freeze/, the committed cache of cell outputs, which exists because nbstripout strips outputs out of the .ipynb files on commit. So _freeze/ — and network_viz/, the PyVis graph built by NB03 — are committed on purpose; they are the only record of the results.

The one rule that follows: after changing notebook code or prose, refresh the freeze in the same commit.

quarto render --execute                 # re-runs notebooks; needs BACI in data/raw/
git add _freeze network_viz && git commit -m "refresh freeze"

Forget it and the publish job fails with a missing-kernel error rather than quietly serving the old output — execute.freeze is set to auto, not true, precisely so that mistake is loud. Editing only .qmd prose or styles/ needs no refresh.

Project structure

src/eu_trade_network/   analysis package
notebooks/              01 → 05 (rendered as pages on the site)
data.qmd · index.qmd    Quarto site: Data & method + Home
data/                   raw/ processed/ (gitignored) · reference/ (committed)
figures/headline/       committed PNGs
_freeze/                committed notebook outputs — the site renders from these
network_viz/            committed PyVis graph, built by NB03

Licence

Code: MIT (see LICENSE). Data: CEPII BACI under Etalab Open Licence 2.0 — attribution required.