Variable dictionary, methodology, and citation policy

Documentation endpoint for the Maddison Project Database. Returns the two variables (GDP per capita and population) with their units and methodology notes, the 8 regional slugs and their canonical names, the release metadata (version, DOI, DataverseNL URL), the CC BY 4.0 citation policy including the special rule requiring per-country source citations for analyses covering fewer than 12 countries, and a short and full academic citation string. Published by Bolt and van Zanden at the University of Groningen under CC BY 4.0.

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application/json

Variable dictionary, region list, methodology, and citation policy.

Bodyapplication/json

Example

{
    "data": {
        "variables": [
            {
                "id": "gdppc",
                "label": "string",
                "unit": "2011 international dollars (PPP)",
                "description": "string"
            }
        ],
        "regions": [
            {
                "slug": "western-europe",
                "name": "Western Europe"
            }
        ],
        "methodology": "string",
        "citation_policy": "string",
        "citation_short": "Maddison Project Database (Bolt & van Zanden, University of Groningen, CC BY 4.0)",
        "citation_full": "string",
        "release": {
            "version": "MPD2023 v1.0",
            "doi": "10.34894/INZBF2",
            "published": "2024-04-26T00:00:00Z",
            "url": "https://dataverse.nl/dataset.xhtml?persistentId=doi:10.34894/INZBF2",
            "file": "mpd2023_web.xlsx"
        },
        "known_historical_codes_absorbed": [
            "SUN",
            "YUG",
            "CSK",
            "SCG"
        ]
    },
    "meta": {
        "endpoint": "/api/v1/fred/us/cpi",
        "data_time": "2026-04-16T14:30:00Z",
        "response_time": "2026-04-16T14:30:12Z",
        "provider": "Sugra API v1.0.1",
        "source": "string",
        "fallback_used": true,
        "fallback_chain": [
            "string"
        ],
        "cached": true
    }
}

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Variable dictionary, methodology, and citation policy

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