Tanzania: the economy “grew” 37% in six months, retroactively
Tanzania: GDP in current dollars
The year was long over: what changed was not events but the count.
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GDP is compiled by national statisticians, and the IMF uses their figures. Every few years a country recalculates its economy: a new base year with new prices, and industries that were not counted before (telecoms, online trade, services). If the old base was dated, the economy “grows” on paper overnight, and with it the shares of debt, taxes and spending in GDP change.
The first two bars: GDP of the same past year in two consecutive IMF editions, in billions of dollars.
- GDP 2012, IMF, Oct 2014
$28.5B (44,718 bn in national currency)
- GDP 2012, IMF, Apr 2015
$39B (61,316 bn in national currency)
All consecutive World Economic Outlook editions 2007–2025 (April and October) compared: GDP at current prices in national currency and in dollars for the latest year both editions treat as actual. Jumps of 20% or more, the same in both currencies (a change of currency, such as joining the euro, moves only the national-currency figure and is left out), in countries of 3 million people or more; for each country, the largest jump.
The IMF follows the country’s revision of its national accounts; the reason differs case by case (a new base year, a new method, new surveys) and the card does not establish it. Real growth in a given year usually changes little; the level does.
A question for this picture
What else changes when an economy grows by tens of percent overnight: debt ratios, taxes, rankings?