The g Nexus
The g factor derives its broad significance from the fact that it is causally related to many real-life conditions, both personal and social. These relationships form a complex correlational network, or nexus, in which g is a major node. The totality of real-world variables composing the g nexus is not yet known, but a number of educationally, socially, and economically critical elements in the nexus have already been identified and are the subject of ongoing research.
Complex statistical methods have been developed for analyzing correlational data to help determine the direction of causality among the elements of the g nexus. These elements include personally and socially significant variables, such as learning disabilities, level of educational attainment, illiteracy, poverty, employment and income, delinquency, crime, law abidingness, and personal integrity.
The limitations of g as an explanatory variable in personal achievements have also been recognized. A person's level of g acts only as a threshold variable that specifies the essential minimum level required for different kinds of achievement. Other, non-g special abilities and talents, along with certain personality factors, such as zeal, conscientiousness, and persistence of effort, are also critical determinants of educational and vocational success.
Since the psychometric basis of g is now well established, future g research will extend our knowledge in two directions. In the horizontal direction, it will identify new nodes in the g nexus, by studying the implications for future demographic trends, employment demands, and strategies for aiding economically developing countries. Research in the vertical direction will seek to discover the