Saturday 6 September 2014

DIFFERENTIAL APTITUDE TEST BATTERY

DIFFERENTIAL APTITUDE TEST BATTERY

INTRODUCTION

Aptitude may be described as a special ability or capacity distinct from the general intellectual ability which helps an individual to acquire the required  degree of proficiency or achieve meant in a specific field .Aptitude is a present pattern of traits but it always  refers to future potentialities or performance .According to Bingham [1937] ‘’Aptitude refers to those qualities characterizing  a Pearson’s way of behavior which serve to indicate how well he can learn to meet and solve a certain specified kinds of problem’’ An  aptitude test , therefore, is one designed to measure a Pearson’s potential ability in an activity of specified  kind and with in a restricted range . Aptitude test helps us to measure the probability of success in an activity such as playing at piano, learning a language, etc. Two types of aptitude test are there Specialized Aptitude Test and General Aptitude Test. Aptitude test can be used for admitting candidates for various types of professional courses, for the purpose of guidance in selecting subjects and also for selecting persons for job.
DIFFERENTIAL APTITUDE TEST 
The Differential aptitude test (DAT) were developed and designed by Bennett, Seashore and Wesman in 1951 which won the Authors Award by the American Personnel and Guidance Association for distinguished work in test construction and publication. This test battery yields eight scores. Tests are available in separate booklets. The entire battery can be administered into sections of approximately 2.25 hours each. They yield a profile in percentage ranks.
                DAT provides a basis for the educational and occasional guidance of students in grades eight through twelve. Subsequently examiners have found that the test is useful in the occasional counseling of young adults out of school in the selection of employees. The test  has been periodically revised  and stands as one of the most popular multiple aptitude test batteries.
                  Differential Aptitude Test consists of eight different abilities. They are explained bellow;
1] Verbal Reasoning: The special type of verbal analogies item utilized in this test in which the first and fourth terms must be chosen by the subject markedly reduces the chances of guessing the correct answer. The best was designed to measure the subject’s ability to handle verbal concepts rather than his word knowledge. Accordingly item difficulty was varied by increasing the complexity of the reasoning involved rather than by the use of more abstruse and unusual words.
2] Numerical Ability: This is a multiple choice arithmetic test covering a variety of operations from simple addition to the extraction of cube root. Some of the items are purely computational while others call for ingenuity and the manipulation of numerical relations. Unlike most arithmetic reasoning tests however this test makes practically no demands upon verbal comprehension since the problems are presented almost exclusively   in numerical terms.
3] Abstract reasoning: This is a series completion test employing abstract patterns or figures. It may be regarded as a non language supplement to the verbal and numerical  tests described above.
4] Space Relations: This test requires the ability to visualize a three dimensional object from a two dimensional pattern as well as ability to imagine how an object would look if rotated in various ways.
5] Mechanical Reasoning: This is a mechanical comprehension test. Each item includes a picture illustrating a mechanical situation which might be encountered in everyday life together with a simply worded question about the picture.
6] Clerical Speed and Accuracy: In this test the subject is instructed to locate identical combinations of letters or number as quickly as possible. Such items are similar to those most commonly employed in special tests of clerical aptitude.
7] Language usage, spelling: In which the subject indicates the incorrectly spelled words in a list. The incorrect spelling employed is those shown by previous investigators to occur most frequently in actual writing.
8] Language usage; Sentences: This test requires the subject to locate errors of grammar, punctuation or word usage in each of a series of sentences. Each sentence may contain from ‘0’ to ‘5’ errors.   These two tests than any of the others in the battery.
                                           In constructing the Differential Aptitude Test the authors were guided by several explicit criteria;
*Each test should be an independent test: There are situations in which only part of the battery is required or desired.
*The test should measure power: For most vocational purposes to which test results contribute the evaluation of power –speeded problem solving is of primary concern.
*The test battery should yield a profile: The eight separate scores can be converted to percentile ranks and plotted on a common profile chart.
*The test materials should be practical: With timed limits of six to thirty minutes per test the entire DAT can be administered in a morning or afternoon school session.
*The test should be easy to administer: Each test contains excellent “warm up” examples and can be administered by persons with a minimum of special training.
*Alternative forms should be available: For purposes of retesting, the availability of alternate forms will reduce any practice effect.
                                         The DAT tests, especially the verbal reasoning plus numerical ability combination are good predictors of high school and college grades. For this reason the combination of ‘VR’ and ‘NA’ is often considered an index of scholastic aptitude.                                                 
   Conclusion

                                           The Differential Aptitude Test has proved very successful in predicting academic success and has been found especially useful for providing educational and vocational guidance. The test shows a mixed pattern of inter correlations with each other which is optimistically interpreted by the as establishing the independence of the eight tests.

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