The studies of trends for MPD and process control parameters in the mills provide a means of identifying problems affecting OER. The observed decline in OER from 1992 onwards in Golden Hope mills could be attributed to the harvesting standards and the quality of the crop harvested. The sharp drop in July 1993 could possibly be confounded with seasonal variation. Improvements in harvesting standards, and milling efficiency with lower level of oil losses will definitely reduce the fluctuation observed in the seasonal variation and arrest or improve the current declining trend in OER.