In bringing together these studies in which we can make somewhat comparable estimates of tested deficiency covering over 9000 delinquents, it seems possible to analyze further the question of the deficient delinquent. Comparison of the amounts of deficiency on an objective basis is scientifically a big step in advance from a reliance upon the subjective opinion of experts who cannot possibly have the same standard of deficiency in their minds. The results of the comparable investigations, on the basis of the above reinterpretation of the borderlines, are brought together in Table XI. The frequency of tested deficiency which is found among about the lowest 0.5 and 1.5% respectively of the population generally is there shown for these different groups of delinquents. This review of the studies thus assembled enables us to correct a number of impressions that have become prevalent by the early studies, as well as to formulate the general data in regard to the deficient delinquent in a manner that places the practical control of this problem on a safer foundation. We shall summarize the data under four heads. TABLE XI. FREQUENCY OF TESTED DEFICIENCY AMONG OVER 9000 DELINQUENTS. _Comparison of the frequency of tested deficiency among objectively selected groups of delinquents reinterpreted on roughly the same borderlines, which are often not those used by the original investigators. “Presumably deficient” in the table corresponds roughly to about the lowest 0.5 per cent., and the doubtful group to about the next 1.0 per cent. in the general population_