The accuracy of U.N. population projections is examined. The goal is to measure the amount of uncertainty associated with past projections of the United Nations in order to provide a reaiistic measure of the uncertainty in the projection that the U.N. makes in the future. Various descriptive measures of the forecast error data set are presented and methods from exploratory data analysis and cluster analysis are applied. The data consists of the medium variant of projections made by the U.N. between 1960 and 1985 for 101 countries. The findings show that the forecasting performance is satisfactory for the majority of countries. However, relatively laxge forecast errors occurred mainly in African countries. In some African countries the population growth has been substantiaüy underestimated.