Go to the site linked in the article: http://iresearch.worldbank.org/PovcalNet/index.htm?1 http://iresearch.worldbank.org/PovcalNet/index.htm?1 See column titl

Go to the site linked in the article: http://iresearch.worldbank.org/PovcalNet/index.htm?1 http://iresearch.worldbank.org/PovcalNet/index.htm?1 See column titled "Pov.line (PPP$/day)" Click on column title to bring up this text: http://iresearch.worldbank.org/PovcalNet/Docs/dictionary.html#PL http://iresearch.worldbank.org/PovcalNet/Docs/dictionary.htm... And there they give you the definition of PPP, aka purchasing power parity, and tell you they are using 2005 rates of consumption.