Differential Aptitude Testing

Differential Aptitude TestingAn individual’s career development and success are influenced by the attributes that differentiate that person from other people. These individual differences include interests, values, traits, motives, and intelligence. Perhaps the most powerful and pervasive individual difference influencing career development is aptitude. A person’s aptitude can influence everything from career choice to entry into a specific career to advancement within that career. This article outlines what is known about the nature of aptitude, the relationship of aptitude to career development outcomes, and the current uses of aptitude testing in the workplace.


Aptitude is defined as a person’s natural ability or capacity for learning. It is also defined as talent within a specific domain. Aptitude testing uses a standardized test designed to predict an individual’s ability to learn certain skills. Aptitude can be theoretically distinguished from the concept of achievement. Achievement is a result gained by effort or the quality and quantity of a student’s work. Achievement testing involves a standardized test designed to measure an individual’s acquired knowledge and skills in a specific domain. However, an individual’s aptitude and achievement are highly related to one another. Aptitude predicts achievement, and achievement strongly predicts capacity for further learning. Thus, there is an inherent ambiguity between achievement and aptitude tests. No test can measure pure aptitude, because previous learning facilitates performance on any item type and all achievement tests act as tests of aptitude as well.

Aptitude and achievement are actually ways of describing individual differences in intelligence. Intelligence in this context can be understood as the entire repertoire of acquired skills, knowledge, learning sets, and generalization tendencies considered intellectual in nature that are available at any one period in time.

The most thorough understanding of the structure of intelligence is John B. Carroll’s hierarchical model. He summarized the large body of intelligence research that spanned the twentieth century. Based on the data available at the time, Carroll applied factor-analytic methods to develop a model of intelligence that incorporated the relationships among the multitude of specific aptitude tests. The resulting model places general intelligence at the top of the hierarchy, with constructs including fluid intelligence, crystallized intelligence, memory, visual perception, auditory perception, retrieval, cognitive speed, and processing speed at the second level. The individual tests of attitude and achievement assess various facets of the third level. This model provides a framework by which the relationships between aptitude tests can be understood.

The presence of a general factor for intelligence has led some to suggest that only general intelligence or general mental ability is useful for predicting performance in most domains. However, highly related constructs can have quite different relationships with other variables. Because of this, different aptitude tests, such as the ones measuring the third-level constructs identified by Carroll, are useful for predicting various career outcomes. The specific aptitudes required in different careers can be discovered through job analysis.

Aptitude Outcomes

Aptitude has been shown to predict a number of important work and career outcomes. These outcomes include career choice, training performance, job performance, and career advancement. Recent work by David Lubinski has revealed interesting trends in the career choices of extremely high-ability children. The area in which high-ability children are most able predicts the careers that they will later choose. This sample is especially interesting, because there are few limits on the careers such individuals can choose, since their aptitude is high in all areas. Philip Ackerman has developed complexes of aptitude, personality, and interests that tend to characterize individuals. These complexes also predict career choice. People tend to enjoy the things they do well and so gravitate toward careers that allow them to use the relative strengths they possess.

The definition of aptitude implies that it should influence an individual’s training performance. Having high ability and capacity for learning in the area in which a person is being trained should lead to a faster and more complete knowledge of the area. This result has been consistently shown in the achievement tests that follow many training programs.

The effect of aptitude does not stop at training but extends into an individual’s performance on the job. One of the most constant findings in the field of industrial/organizational psychology is that general mental ability (aptitude) predicts job performance. Frank Schmidt and John Hunter conducted a meta-analysis of all the major selection procedures used over an 85-year span, and general mental ability was found to be among the strongest predictors of job performance. The relationship between general aptitude and performance also reliably increases as the complexity of the job increases. The main way that aptitude influences job performance is through the acquisition of job knowledge. Individuals with high aptitude learn more, and individuals who know more perform better. Recent work on understanding the multidimensional nature of job performance by John Campbell has led to a broader understanding of the nature of performance. The inclusion of various dimensions of job performance allows for differential prediction of those dimensions. Specific aptitudes influence performance in the dimensions of job performance that require the abilities and learning that constitute those aptitudes.

Aptitude also influences career advancement. Aptitude facilitates job performance, which typically leads to career advancement. Aptitude not only contributes to the performance that leads to promotions but also influences success within the new position, which leads to further advancement. Because of evidence showing the powerful effects of aptitude on performance, many organizations across a variety of fields and careers use information from differential aptitude testing as they make human resource decisions.

Aptitude Testing in Practice

Aptitude testing has been used for almost every sort of human resource decision faced by organizations. Many organizations include cognitive-ability tests to screen employees for selection. Even the National Football League uses an aptitude test to provide additional information about possible draft picks. Organizations use aptitude tests to manage their human capital. They identify the most likely candidates for future advancement so that they can invest extra resources into those individuals’ development. Aptitude testing is not limited to traditional cognitive-ability testing. Recent development of tests of social or emotional intelligence and situational judgment represent attempts to measure individual differences in aptitude so that organizations can better use their human capital.


Aptitude testing has been shown to be effective for identifying individuals who will be successful across a broad spectrum of careers. Because of its power for predicting these vital outcomes in a competitive economic environment, it will most likely continue in its dominant position in human capital decisions and thus in successful career advancement. As our understanding of job performance and the aptitudes that influence it increases, the form of differential aptitude tests will undergo changes. However, differential aptitude will continue to play a key role in our understanding of career development.

See also:


  1. Ackerman, P. L. and Beier, M. E. 2003. “Intelligence, Personality, and Interests in the Career Choice Process.” Journal of Career Assessment 11:205-218.
  2. Campbell, J. P. 1991. “Modeling the Performance Prediction Problem in Industrial Organizational Psychology.” Pp. 445-505 in Handbook of Industrial and Organizational Psychology, edited by M. D. Dunnette and L. M. Hough. Palo Alto, CA: Consulting Psychologists Press.
  3. Carroll, J. B. 1993. Human Cognitive Abilities: A Survey of Factor-analytic Studies. New York: Cambridge University Press.
  4. Drasgow, F. 2003. “Intelligence and the Workplace.” Pp. 107­-130 in Comprehensive Handbook of Psychology. 12, Industrial and Organizational Psychology, edited by W. C. Borman, D. R. Ilgen and R. J. Klimoski. New York: Wiley.
  5. Schmidt, F. L. and Hunter, J. E. 1998. “The Validity and Utility of Selection Methods in Personnel Psychology: Practical and Theoretical Implications of 85 Years of Research Findings.” Psychological Bulletin 124:262-274.
  6. Webb, R. M., Lubinski, D. and Benbow, C. P. 2002. “Mathematically Facile Adolescents with Math-science Aspirations: New Perspectives on Their Educational and Vocational Development.” Journal of Educational Psycho­logy 94:785-794.