Miscellaneous Technical Details

This includes technical details that don't go anywhere else and should be noted. Some of these are "note for later" items.

UN Data

Currency Conversion

In the AMA "Analysis of Main Aggregates" data, the currency conversion is handled in a particular mannner.

Once the national accounts data in national currency are complete, the current and constant price series are converted into US Dollars by applying the corresponding market exchange rates as reported by the IMF. When these conversion rates are not available other IMF rates are used (official rates or principal rates).

...

In cases where a country experiences considerable distortion in the conversion rates, the United Nations Statistics Division uses price-adjusted rates of exchange (PARE) as an alternative to the exchange rates reported by the IMF or UN operational rates of exchange. The conversion based on PARE corrects the distorting effects of uneven price changes that are not well reflected in the other conversion rates. Consequently, unrealistic levels in GDP and other national accounts aggregates expressed in US Dollars may have been adjusted for certain time periods to improve the economic analysis at national, regional and local levels.

There is proper specification of this in methodology PDF.

The per year currency conversion source --IMF, PEAR, or other-- for each country is noted in the "Exchange rate and population" file Download-Xpop.xls.

This means some care should be taken if performing currency conversions on other data that is used in the pipeline: it must be matched with how the UN has done the currency conversion for each country within each year.