Despite Spearman arguing that "g" was what emerged from a large battery of tests, i.e., that it was not measured perfectly by any single test, the fact that g-theory suggested that much of ability could be captured in a single factor, and his suggestion that "the eduction of relations and correlates" underlay this general factor led to the quest for tests of this general ability. Raven's Progressive Matrices might be regarded as one of these although Raven himself clearly stated that his tests should not be regarded as "intelligence" tests.