According to Paul Muchinsky in his textbook Psychology Applied to Work, "Mechanical aptitude tests require a person to recognize which mechanical principle is suggested by a test item. The underlying concepts measured by these items include sounds and heat conduction, velocity, gravity, and force. One of the more popular tests of mechanical reasoning is the Bennett Test of Mechanical Comprehension. The test is a series of pictures that illustrate various mechanical concepts and principles. Other tests of mechanical comprehension have also been developed. Tests of mechanical ability are highly predictive of performance in manufacturing/production jobs. However, women traditionally perform worse than men on tests of mechanical ability. Recent attempts to include test questions pertaining to kitchen implements and other topics about which women are more familiar have reduced, but not eliminated, the male/female score differential." 
- 1 Background Information
- 2 Uses of Mechanical Aptitude Test
- 3 Types of Tests
- 4 References
Aptitude tests have been used for military purposes since World War I to screen recruits for military service. The Army Alpha and Army Beta tests were developed in 1917-1918 so ability of personnel could be measured by commanders. The Army Alpha was a test that assessed verbal ability, numerical ability, ability to follow directions, and general knowledge of specific information. The Army Beta was its non-verbal counterpart used to evaluate the aptitude of illiterate, unschooled, or non-English speaking draftees or volunteers.
During World War II, the Army Alpha and Beta tests were replaced by The Army General Classification Test (AGCT) and Navy General Classification Test (NGCT). The AGCT was described as a test of general learning ability, and was used by the Army and Marine Corps to assign recruits to military jobs. About 12 million recruits were tested using the AGCT during World War II. The NGCT was used by the Navy to assign recruits to military jobs. About 3 million sailors were tested using the NGCT during World War II.
Additional classification tests were developed early in World War II to supplement the AGCT and the NGCT. These included:
- Specialized aptitude tests related to the technical fields (mechanical, electrical, and later, electronics)
- Clerical and administrative tests, radio code operational tests
- Language tests and driver selection tests.
Mechanical Aptitude and Spatial Relations
Mechanical aptitude tests are often coupled together with spatial relations tests. Mechanical aptitude is a complex function and is the sum of several different capacities, one of which is the ability to perceive spacial relations. Some research has shown that spacial ability is, for some jobs, the most vital part of mechanical aptitude. Because of this, spacial relations tests are often given separately or in part with mechanical aptitude tests.
There is no evidence that states there is a general intelligence difference between men and women. However, there is a difference in the cognitive abilities between the two sexes. Males tend to do better on the quantitative tasks and the visual-spatial skills then females, and females tend to score much higher than men on the verbal sections of the test. Males have always performed very high on the mechanical aptitude tests; much higher than women. In recent years, another mechanical aptitude test was created. The main purpose of this test was to create a fair chance for women to perform higher than, or at the same level as men. Males still perform at a much higher level than women, but the scores between men and women have been drawn closer together. There is little research that has been devoted as to why men are able to complete the tests and perform much higher than women.
Uses of Mechanical Aptitude Test
The major uses for mechanical aptitude testing are:
- Identify candidates with good spatial perception and mechanical reasoning ability
- Assess a candidate's working knowledge of basic mechanical operations and physical laws
- Recognize an aptitude for learning mechanical processes and tasks
- Predict employee success and appropriately align your workforce
These tests are used mostly for industries involving:
The major occupations that these tests are relevant to are:
- Automotive and Aircraft Mechanics
- Industrial/Technical (Non-Retail) Sales Representatives
- Skilled Tradesperson such as Electricians, Welders, and Carpenters
- Transportation Trades/Equipment Operators such as Truck Driver and Heavy Equipment Operator 
Types of Tests
Barron's Test of Mechanical Aptitude
The Barron's Test, which is also called the Armed Services Vocational Aptitude Battery (ASVAB), was the most widely used mechanical aptitude test in the world. The test consists of ten subject specific tests that measure your ability to perform separate job related areas and provides an indication of your level of academic ability. The ASVAB was used very often in the 1920s and 1930s, especially by the military. The military would ask that all recruits take this exam to help them be placed in the correct job while enrolled in the military. In the beginning, World War I, the U.S. Army developed the Army Alpha and Beta Tests, which grouped the draftees and recruits for military service. The Army Alpha test measured recruits' knowledge, verbal and numerical ability, and ability to follow directions using 212 multiple-choice questions.
However, during World War II, the U.S. Army had replaced the tests with a newer and improved one called the Army General Classification Test. The test had many different versions until they improved it enough to be used regularly. The current tests consist of three different versions, two of which are on paper and pencil and the other is taken on the computer. The scores from each different version are linked together, so each score has the same meaning no matter which exam you take. Some people find that they score higher on the computer version of the test than the other two versions, an explanation of this is due to the fact that the computer based exam is tailored to their demonstrated ability level. These tests are beneficial because they help measure your potential; it gives you a good indicator of where your talents are. By viewing your scores, you can make intelligent career decisions. The higher score you have, the more job opportunities that are available to you.
Wiesen Test of Mechanical Aptitude
The Wiesen Test of Mechanical Aptitude is a measure of a person's mechanical aptitude which is referred to as the ability use machinery properly and maintain the equipment in best working order. The test is 30-minutes and has 60-items that can help predict performance for specific occupations involving the operation, maintenance, and servicing of tools, equipment, and machinery. Occupations in these areas require and are facilitated by mechanical aptitude. The Wiesen Test of Mechanical Aptitude was designed with the intent to create an evolution of previous tests that helps to improve the shortcomings of these earlier mechanical aptitude tests, such as the Bennett Test of Mechanical Comprehension. This test was reorganized in order to lessen certain gender and racial biases. The reading level that is required for the Wiesen Test of Mechanical Aptitude has been estimated to be at a sixth-grade level, and it is also available in a Spanish-language version for Spanish speaking mechanical workers. Overall, this mechanical aptitude test has been shown to have less of an adverse impact than previous mechanical aptitude.
There are two scores given to each individual taking the test, a raw score and a percentile ranking. The raw score is a measure of how many questions (out of the 60 total) the individual answered correctly, and the percentile ranking is a relative performance score that indicates how the individual's score rates in relation to others people who have taken this particular mechanical aptitude test and how they scored.
Average test scores for the Wiesen Test of Mechanical Aptitude were determined by giving the test to a sample of 1,817 workers aged 18 and older working in specific industrial occupations that were mentioned previously. Using this sample of workers, it was determined that the Wiesen Test of Mechanical Aptitude has very high reliability (statistics) (.97) in determining mechanical aptitude in relation to performance of mechanical occupations. 
Bennett Test of Mechanical Comprehension
The Bennett Mechanical Comprehension Test (BMCT) is an assessment tool for measuring a candidate's ability to perceive and understand the relationship of physical forces and mechanical elements in practical situations. This aptitude is important in jobs and training programs that require the understanding and application of mechanical principles. The current BMCT Forms, S and T, have been used to predict performance in a variety of vocational and technical training settings and have been popular selection tools for mechanical, technical, engineering, and similar occupations for many years.
The BMCT is composed of 68 items, 30-minute time limited test, that are illustrations of simple, encountered mechanisms used in many different mechanisms. It is not considered a speeded time test, but a timed power test and the cut scores will provide the different job requirements for employers. The reading and exercise level of concentration for this test is below or at a sixth-grade reading level.
In current studies of internal consistency reliability, the range of estimates were compared from previous studies and found out the range was from .84 to .92. So this shows a high reliable consistency when taking and measuring the BMCT. Muchinsky (1993) evaluated the relationships between the BMCT, a general mental ability test, and an aptitude classification test focused on mechanics, and supervisory ratings of overall performance for 192 manufacturing employees. Of the three tests, he found the BMCT to be the best single predictor of job performance (r = .38, p < .01). He also found that the incremental gain in predictability from the other tests was not significant.
From a current employer standpoint, these people are typically using cognitive ability tests, aptitude tests, personality tests and etc. And the BMCT has been used for positions in positions such as electrical and mechanical positions. Also companies will use these tests for computer operators and operators in manufacturing. This test can also help eliminate any issues or variables to employers about who may need further training and instruction or not. This test will help show employers who is a master of the trade they are applying for, and will also highlight the applicants who still have some "catching up" to do.
Stenquist Test of Mechanical Aptitude
The Stenquist Test consist of a series of problems presented in the form of pictures, where each respondent would try to determine which picture assimilates better with another group of pictures. The pictures are mostly common mechanical objects which do not have an affiliation with a particular trade or profession, nor does the visuals require any prior experience or knowledge. Other variations of the test are used to examine a person’s keen perception of mechanical objects and their ability to reason out a mechanical problem. For example, The Stenquist Mechanical Assemblying Test Series III, which was created for young males, consisted of physical mechanical parts for the boys to individually construct items with.
- Muchinsky, Paul (2012). Psychology Applied to Work. Summerfield, NC: Hypergraphic Press. p. 105. ISBN 978-0-578-07692-8.
- "History of Military Testing". Retrieved 25 April 2012.
- Levy, Joan (2004). Master the Mechanical Aptitude and Spatial Relations Tests. Thomson Peterson's. p. 2. ISBN 978-0-7689-1699-7.
- Christensson Ringby, Karolina (2001-01-01). "Sex Differences in Mechanical Aptitude: An Investigation of Sex Differences in Mechanical Aptitude and Its Relation to Nonverbal Abilities". the Osprey Journal of Ideas and Inquiry. All Volumes: 53–57. Retrieved 12 April 2012.
- "Pearson TalentLens". Bennett Mechanical Comprehension Test. Pearson Education, Inc. Retrieved 24 April 2012.
- [(http://www.pearsonassessments.com/HAIWEB/Cultures/en-us/Productdetail.htm?Pid=015-8341-430&Mode=summary) "Bennett Mechanical Comprehension Test"].
- Duran, Terry L. (2009). Major, U.S. Army. New York: Barron's Educational Series. pp. 3–9. ISBN 13: 978-0-7641-9546-4 Check
- "WTMA: Wiesen Test of Mechanical Aptitude". Criteria On-Demand Assessment. Retrieved 12 April 2012.
- Bennett, George (2008). Bennett Mechanical Comprehension Test. Pearson. p. 84.
- Cooper, C. L. (1 January 1936). "Mechanical aptitude and school achievement of negro boys.". Journal of Applied Psychology 20 (6): 751–760. doi:10.1037/h0057489. Retrieved 1 May 2013.
- McElwee, E. W. (1 January 1932). "Standardization of the Stenquist Mechanical Assemblying Test Series III.". Journal of Educational Psychology 23 (6): 451–454. doi:10.1037/h0071233. Retrieved 2 May 2013.