Data sources
Lewis integrates public data from official statistical agencies and international organizations, all free to access:
- United States — Bureau of Economic Analysis (International Transactions & International Investment Position)[1][2]; Federal Reserve Economic Data (FRED)[3]; U.S. Treasury.
- United Kingdom — Office for National Statistics, Balance of Payments (The Pink Book).[4]
- Germany — Deutsche Bundesbank, Balance of Payments Statistics.[5]
- Global — World Bank World Development Indicators[6]; IMF; OECD.
All balance-of-payments data are aligned to the IMF's sixth edition manual (BPM6).[7]
Standardization
Country panels are expressed as a share of GDP for cross-country comparability; higher- frequency series are aggregated to annual. The current-account / financial-account identity (CA + KA + FA ≈ net errors & omissions ≈ 0) is verified during construction.
Transfers of value
The ITV master panel applies Köhler's monetary measure of unequal exchange[8], with countries grouped into world-system classes. The framework draws on the Prebisch–Singer terms-of-trade tradition[9][10] and, more distantly, on Lewis's dual-sector model of development.[11]
Reproducibility & freshness
Every chart reads from a Parquet cache built deterministically from the project's Outputs/
tree; every dataset is downloadable in CSV, Excel, and Parquet from the
data catalog. Datasets with a public-API source are snapshotted automatically and
carry a live badge; a fetch that fails validation never overwrites good data.
Limitations
Country coverage for the deep balance-of-payments panels is limited to the US, UK, and Germany by data availability; global coverage (World Bank, ITV) is broader but shallower. The U.S. flow-of-funds section currently rests on the BEA International Investment Position series.
Philosophy — how Lewis reads international economics
Lewis takes a point of view. The recorded balance of payments is an accounting identity, not an explanation: a current-account deficit is mirrored by a financial-account surplus, but the identity says nothing about who finances whom, what they buy, and who profits. Those are the questions Lewis treats as primary.
Three commitments follow. First, flows and stocks are read together: a deficit is only fully understood through the international investment position it accumulates into, and the income that position throws off. Second, composition matters more than totals: the same dollar of foreign financing has very different consequences depending on whether it buys a Treasury bill or a share of stock — the instrument determines the return foreigners ultimately extract. Third, the data must be honest about its own limits: where a series needed to settle a question is not in hand, Lewis says so and shows what it has, rather than manufacturing a number to complete the picture (see the "Recently shipped" and limits notes above for exactly what is, and is not, yet in the cache).
The result is a forum, not a verdict. The "exorbitant privilege" and its possible erosion are posed as an empirical question the reader can interrogate with the actual data, downloadable in full.