The following is from a 15 March 2012 news item by the World Trade Organization.
The WTO and the Organization for Economic Co-operation and Development (OECD) have signed a letter of understanding to develop statistics on trade in value added. Among other things, the two organizations will produce a publicly-available database of trade flows estimated in value-added terms.
This item is available in its entirety at:
http://www.wto.org/english/news_e/news12_e/miwi_15mar12_e.htm