d2 - The d2 Test of Attention
PURPOSE
Used for selection into job roles where high levels of concentration and visual attention are required, especially where assessment needs must be balanced against cost-effectiveness, reputation and safety. It has particular salience with occupations where high levels of attention are required over a sustained period of time.
The d2 has relevance to roles where errors in work can have significant consequences on overall performance and achievement; job roles such as editing, proof reading and data entry and other roles where errors are particularly costly to overall performance. The instrument has also shown value in areas of industry where attention to detail is paramount for safety such as manufacturing; in some industries and work roles, this can literally be a matter of life and death.
AUTHOR
R. Brickenkamp and E. Zilmer
DESCRIPTION
Originally developed to measure driver aptitude and skill, the d2 has become one of the most widely used measures of attention, particularly visual attention, throughout Europe. In recent years it has become increasingly popular in the USA. It is now in its ninth edition following 40 years of effective use. Areas of usage include transport sectors, pharmaceutical sectors, sports psychology, educational psychology and clinical psychology. Can be administered using paper and pencil materials or on a pc.
The technical manual contains instructions for administration, scoring and interpretation as well as documenting statistical research to date and the extent to which the d2 test fulfils standard test criteria. Reliability (internal & test-retest) is high. Criterion, construct and predictive validity have been demonstrated in numerous research studies. Extensive norms according to age, sex and education are included.
The test itself (in its paper-and-pencil form) consists of a single 'recording blank'. The front page of this is reserved for recording the respondent's personal data and performance results. There is also a practice example so that the respondent can become acquainted with the task. On the reverse side is the standardised test form in a landscape layout of 14 test lines with 47 characters in each line. Each character consists of a letter, 'd' or 'p' marked with one, two, three or four small dashes. The respondent is required to scan the lines and cross out all occurrences of the letter 'd' with two dashes while ignoring all other characters.
Two scoring keys are provided; one for identifying errors of omission (missing characters that should have been crossed out) and one for identifying errors of commission (crossing out characters that should not have been crossed out).
The test results in the following norm-referenced scores:
Total Number of items processed (TN) is the sum of all items processed whether correctly or incorrectly. It is a highly reliable measure of processing speed.
Percentage of Errors (E%) measures the qualitative aspects of performance. It represents the proportion of errors made across all items processed. The smaller the percentage of errors, the better the subject’s accuracy.
Total number of items processed minus errors (TN-E) provides an indication of the implications of the combined speed and accuracy scores for attentional and inhibitory control.
Further qualitative evaluation can take account of:
Concentration Performance (CP) is the number of correctly processed items minus errors of commission. This score cannot be distorted by such tendencies as the haphazard skipping over of sections of the test or crossing out all letters without discriminating among them. This therefore provides a check on distortion in response style.
Fluctuation rate (FR) is indicated by the discrepancy between the line with the maximum number of items processed and the line with the minimum of items processed. Extremely high raw scores can suggest an inconsistency in work speed perhaps related to poor motivation.
RELIABILITY
Internal consistency coefficients for TN, TN-E and CP are above .90 regardless of the statistics used or the sample. Test-retest coefficients were all above 0.7 for these three scales.
VALIDITY
A large volume of research documents the validity of this test. Research studies in clinical psychology, pharmacology, educational psychology, vocational counselling, industrial psychology, sports psychology and traffic psychology support the multiple clinical and empirical applications of the d2 test.
NORMS
Extensive European norms for the paper version (N< 6000). Normative data for the electronic version currently consists of two groups: 1187 apprentices undergoing selection for job roles and 261 people in rehabilitation.
DURATION
Eight minutes including administration
TEST MATERIALS |
£
|
| Starter set: 1 Manual, 50 record blanks, 1 set of scoring keys |
92.00
|
| Manual |
54.00
|
| Record blanks (consumable) x50 |
20.00
|
| Scoring keys x2 |
24.00
|
| |
|
d2 Offline |
Cost per test |
| HTS System & Installation required at each location |
240.00
|
| d2 Offline 1 Test |
8.00
|
| d2 Offline 2-9 Tests |
7.60
|
| d2 Offline 10-19 Tests |
7.20
|
| d2 Offline 20-49 Tests |
6.80
|
| d2 Offline 50-99 Tests |
6.40
|
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