Modern psychology applies various tests to assess concentration performance. One of the most commonly used tests, even today, is the d2 test. It is an attention stress test developed by German psychology professor Rolf Brickenkamp in 1962. Participants are individuals, but also whole groups of subjects.
What is the d2 test?
Modern psychology applies various tests to assess concentration performance. One of the most commonly used tests, even today, is the d2 test. The d2 test was designed by the Technical Inspection Agency (TÜV) for people who wanted to apply for a job as a professional driver. It is suitable for people from 9 to 60 years of age and assesses the ability to concentrate on a specific job for a certain period of time while performing as error-free as possible (high work accuracy). The d2 test meets the criteria of validity, reliability and objectivity required for standard tests. It is easy to use. Test execution and evaluation require only little time. In addition, it has a high efficiency and causes only low costs. Currently, the revised version d2-R and the PC version (d2-C) are available. The results of the test represent the typical, but not the maximum, attentional performance of the respective participant.
Function, effect, and goals
The d2 test is most commonly used in child and adolescent psychiatry (educational and school counseling). Other areas of application include traffic psychology, clinical psychology, and neuropsychology. In career counseling and occupational attitude tests, it is used to determine whether applicants are suitable for the advertised position. The reliability of the d2 is currently estimated at 95 to 98 percent in all three tested areas of speed, accuracy and consistency. The attention test takes about 8 minutes to complete. The actual test takes about 4 minutes and 40 seconds. After the d2 has been administered, a standardized evaluation is carried out using a set of templates (time: approx. 5 minutes) and the test result is interpreted. The d2 consists of 14 lines with 47 (now 57) p and d characters. The two letters are assigned 1 to 4 strokes each, arranged above, below, and above and below. The subject has 20 seconds for each row. She is to cross out as many d’s as possible with two strokes (hence the name of the test). D’s with one, three, and four strokes may not be crossed out. All p’s must not be crossed out at all. The goal is to make as few errors as possible, although character omissions are also considered errors. The administration of d2 is as follows: The test leader explains to the test takers exactly what is to be done. Then a mock run-through takes place. After the start of the actual test, he gets the test takers to work on the next line after every 20 seconds. In the evaluation, all confusion and omission errors are added together, divided by the total number of characters processed and then multiplied by 100 (error rate). Omission errors are characters that must be deleted but were not deleted by the test person. In the case of confusion errors, incorrect characters are deleted. Errors of omission occur more frequently in the d2 test than errors of confusion. The calculation of the error rate according to the conventional method is nowadays replaced by the so-called concentration power value, since this indicator is considered to be more resistant to falsification than the total power minus the number of errors. To determine it, the confusion errors are subtracted from the number of correctly crossed out characters. To find out how concentration ability decreases over the course of the d2 test, a working curve is created. To do this, the test administrator connects the last characters worked on in each case. Another way to find out how the attention curve progresses is to divide the test into two halves and calculate a separate error rate for each. Possible test results are: highly concentrated (great care, high work rate), pedantic (great care, low work rate), disturbed concentration (low care, low work rate), and skip syndrome. It is characterized by many omission errors and must be interpreted in a differentiated way.The d2 concentration test is not applicable to people with brain-organic disorders and behaviorally disturbed children, as it does not allow any precise statements to be made about the actual performance of these test subjects. However, some test administrators perform it on the latter and then interpret the established test results accordingly with caution.
Risks, dangers, and special features
The d2 test in its revised 2010 version (d2-R) contains the original item type, but it has been re-normed to include more characters. In addition, the instructions are more detailed and the scoring of the result is simpler. Despite its standardization and high informative value, experts recommend that the d2 not be used as the sole test for assessing concentration performance, since impairing factors repeatedly occur during the test procedure. For example, the test result is negatively influenced by motivational deficits and emotional and situational problems. Another problem is the skip syndrome: Very many characters are processed, and the error rate is extremely high. Also previously undiagnosed acute visual disturbances, a motor restriction of the writing hand and behavioral disorders can falsify the test result. In addition, negative fake results repeatedly occur when the d2 test is administered. In the case of test takers who have worked through all the characters but have achieved an extremely high number of mix-up errors, it is reasonable to suspect that they are deliberately trying to score worse on the d2 test than they actually are. For older test takers, there are no deviating criteria in the d2 test.
