Test d2
The d2 test is a psychological test from the performance test family , which is used to assess attention ( concentration ). It was developed by the psychology professor Rolf Brickenkamp in 1962 for the aptitude selection of drivers. In the meantime, a computer-based (d2-C) and a revised version (d2-R) of the classic d2 test are also available.
Application area
The test claims to measure the ability to concentrate (or concentrated attention) and is a valid test method for the age range between 9 and 60 years. It can be used in almost all psychological areas (e.g. traffic psychology , neuropsychology and clinical Psychology ). Due to the high efficiency, the low material consumption and the quick implementation, the d2 is one of the most common concentration tests in Germany.
construction
The test consists of the letters d and p , which are arranged in 14 rows of 57 (previously 47) characters each and are marked with 1 to 4 lines at the top and / or bottom.
The test person's task is to cross out as many of the d marked with 2 lines as possible in each row within 20 seconds and not produce any omissions or mistakes: A d that has more or less than two lines must not be crossed out. Likewise, a p must never be crossed out, regardless of how many dashes it is marked with.
The test can be carried out individually or in groups. The examiner explains in detail how to carry out the test and asks you to work as quickly as possible, but without errors. First there is a trial run. The examiner then gives the start signal and prompts you to switch to the next row of characters every 20 seconds. The test, including the instructions, takes approx. 8 minutes, of which approx. 4 minutes and 40 seconds are allotted to the processing time.
evaluation
In order to ensure objectivity, reliability and validity , standardized evaluation instructions are available. The evaluation is done manually and takes about five minutes. The following parameters must be counted or calculated for an appropriate interpretation of the test results.
Characteristics of the d2-R
The following parameters are calculated for the d2-R, the most important of which is the concentration performance . In addition, the characteristic value BZO is interpreted in terms of work speed and the characteristic value F% in terms of accuracy.
- BZO - number of processed target objects: the last painted target object ( d with two lines) per line (summed over all lines)
- AF - omission error: missed or omitted target objects (up to the last painted target object; false negative)
- VF - confusion error: erroneously painted target objects (false positives)
- KL - concentration performance: number of discovered (crossed out) target objects minus number of mistakes (BZO - AF - VF)
- F% - percentage of errors: relative frequency of errors during processing (100 × (AF + VF) / BZO)
Characteristic values of the d2
The following parameters are calculated for the old d2:
- F ( raw error value ): Sum of all errors F 1 and F 2
- F 1 ( omission error ): Number of relevant d with two dashes that were not marked. Only the omissions up to the last marked character in the respective line are counted.
- F 2 ( mix-up error): Number of characters marked by mistake.
- F% ( error percentage): Percentage of errors (F) relative to the number of processed characters (GZ), ie F * 100 / GZ.
- GZ ( total number of all processed characters ): The number of characters from the start of the line to the last marked character is measured.
- GZ-F: This calculation is intended to compensate for when a subject makes more mistakes by working quickly. The test person would then have processed more characters, but also overlooked more characters or marked too many.
- GZ-2F ( “true” total performance value ): This formula was proposed by Oehlschlägel and Moosbrugger (1991) as a “true” total performance value, whereby errors are weighted twice. It is assumed here that two more characters than usual could be processed per error.
- KL ( concentration performance value ): Number of correctly crossed out characters minus the number of mistakes made by mistake (F 2 ). This value is considered to be the most resistant to adulteration, in contrast to GZ-F and GZ-2F.
- SB ( fluctuation range ): Difference between maximum and minimum part-time work per line, ie GZ maximum -GZ minimum .
When the total number of edits is exceptionally high and the percentage of errors (F%) is also abnormally high, it is called skip syndrome.
In addition, a working curve can be visualized by connecting the last edited characters of a line (GZ) with each other. This shows whether the concentration decreased in the course of the processing.
For the same purpose, the error sums of the first and second test halves are compared with one another.
Objectivity, reliability and validity
Uniform test material and standardized instructions ensure that implementation and evaluation are objective. The objectivity of interpretation is also guaranteed by norms for different age groups and by transforming the raw values into standard values.
Based on the calibration sample of here N = 4019, the following characteristic values are reported in the manual of the d2-R. The internal consistency ( Cronbach's Alpha ) for the concentration performance ( KL ) is .96, for the other parameters the values are between r = .80 and r = .96 and can therefore be assessed as very good. The split-half reliabilities are also in the range of .76 - .94 ( KL : .94). The retest reliabilities (N = 118) are at a time interval of 10 days with values of .92 ( BZO ), .85 ( KL ), .47 ( F% ), .42 ( AF ) and .08 ( VF ).
Limited suitability of the test
Since the d2 test requires the ability to perceive and differentiate between visual stimuli, it is not meaningful for test subjects with impaired vision. This limited suitability is not explicitly stated in the instructions for the test and it is only asked whether a visual aid is required and whether it is available. However, since reduced eyesight cannot always be fully compensated by a visual aid, this query does not guarantee a meaningful test result.
Normalization
| designation | Survey year | Sample size (N) | Age range | Remarks |
|---|---|---|---|---|
| Calibration sample d2-R | 2007/2008 | 4024 | 9-60 divided into 7 age groups (see below ) |
* There were no significant gender differences. * BW , BE , BB , HH , HE , NW * Standard values and percentile ranks for KL , BZO , F% per age group |
| BfA (Federal Employment Agency) | 1994 | 3275 | 19-45 | * does not include subjects with a higher educational level (university level) * from all federal states |
| Calibration sample d2 | 2000 | 3176 | (9-10, 11-12, 13-14, 15-16, 17-19, 20-39, 40-60) | * The sample was collected from November 1999 to May 2000. * All levels of education are included here. * Only the federal states of Berlin, Brandenburg, Saxony and Bavaria are represented. * Although the life span between 9 and 80 was recorded (N = 3251), due to the insufficient number of older people, only age groups between 9 and 60 were tabulated (N = 3176). |
| French standard | 1998 | 718 | <25, 25-34, 35-44,> 44 | |
| US standard | provisionally | 506 |
Revision of the d2 and new version d2-R
The revised version of the d2 test from 2010 contains the same type of task as the d2. Apart from the fact that the test has been re-standardized, the newer version also contains more detailed instructions (with linguistic adaptations) and copy sheets for easier evaluation of the results.