National yield statistics
Statistics on planted area, yield and production volume are collected from national statistical services of all EU member states by EUROSTAT. Within the EU, no single Community system to establish these statistics exists: the methods applied vary from country to country. Through article 3 of CAP regulation 837/90, the Commission attempts to harmonise these methods and to stimulate the use of scientific procedures. This regulation prescribes amongst others that censuses or representative sample surveys shall obtain data on planted area, yield and production volume for all significant crops.The heterogeneity in agriculture statistics at EU and country level causes difficulties in collecting, comparing and aggregating the data at Community level affecting timeliness. Bradbury (1994) investigated the applied methods to establish statistics for cereals for various EU member states. The author concluded that ‘most member states attempt to estimate sampling errors, and usually manage to show that the margins are close enough to those set out in regulation 837/90, but with greater or lesser amount of convincing detail. For judgmental assessment of yield/production (and for Greece , of area as well) no fully satisfactory methods to establish the estimating error are available.