Studies on a population of Hevea seedlings revealed a close relation of test tapping yield with the yield of the first year regular tapping and a drop in correlation value with the subsequent yield. The mean yield of three rounds of test tapping was more reliable than that of one round alone. Analysis of the data on yield and girth with a view to looking into the possibility of further improvements in the early evaluation methods, revealed a fair degree of highly significant positive correlation of the girth at test tapping with the mean yield of test tapping (r=0.4630, p<0.010). Its influence on the first year yield of regular tapping with the mean yield of test tapping (r=0.1869, p<0.05) and the correlation with the mean yield over five years of tapping was not significant. Similar trend was noted in the relationship of the girth at opening with the first year yield of regular tapping (r=0.1832, p<0.05) and the correlation with the mean yield over five years of tapping was not significant. Similar trend was noted in the relationship of the girth at opening with the first year yield of regular tapping (r=0.2248, p<0.01) and with the mean yield over five years of tapping (r=0.1832,p<0.05) although there was high relations among the girth at different stages. On the contrary the girth increment on tapping was highly correlated with the yield increment on tapping (r=0.7023,p<0.01). This indicated that girth increment govern the yield more than the actual girth. Hence, for further improvement in early evaluation methods potential of the tree for high rate of girth increment on tapping should also be identified at the early growth phase.