Two trial inter-correlation scores for a large group of airmen as shown in Appendix A, Table 5. Although low enough to warrant the use of each sub-test as a potential predictor, the common factor called “finger dexterity” caused the authors to conclude that each of the placement test measured “ability to make rapid, skillful, controlled manipulative movements of small objects, where the fingers are primarily involved”. Assembly tests appear to measure an additional factor, which these authors called “manual dexterity” and defined as the “ability to make skillful, controlled arm-hand manipulations of larger objects”. Several additional validity studies have been conducted as shown in Appendix A, Table 6-7. When lower correlation are shown, it may be due to the fact that employees were utilized in most cases, rather than applicants providing a restricted range of scores of persons already selected to have good dexterity.