When vocational aptitude batteries are expanded by adding new tests, t
he most common way to measure validity gains is to regress various cri
teria onto the subtest scores from the old and new batteries and contr
ast the results. A rarely tried approach that may be of equal value, h
owever, is to examine ''accidental'' validity gains for a recalculated
general intelligence (or g) score based on the new battery, because m
any psychologists have argued that the majority of test validity comes
from g rather than specific abilities. In this article, we examine va
lidity differences for a g score calculated on the Armed Services Voca
tional Aptitude Battery (ASVAB) alone versus the ASVAB plus nine diver
se experimental tests selected for their potential importance and uniq
ueness from the ASVAB. Although no validity gain for expanded g was ob
served for final school grade criteria, a 6% validity gain was obtaine
d for hands-on performance measures. A gain of this size is of practic
al importance in the armed forces.