non-cash payment system; the design of a common currency. In addition there is the establishment of a common central bank, working through the West Africa Monetary Institute, leading to the introduction of a common currency, the ECO. 3.14 Harmonization of Ghana’s economic policies with those of RECs The country has made steady progress has been made on policy harmonization and institutional arrangements. 3.14.1 Convergence criteria Ghana achieved all four primary criteria. There was, however, no improvement in Ghana’s performance on the secondary convergence zone. 3.14.2 Statistical harmonization Ghana is using Revision 4 of SNA 93 to compile its National Account and is working towards the adoption of the ECOWAS proposal of SNA 2008. Sixth Annual APRM Progress Report: January – December 2011 63