Three targets hidden among ten look-alikes
Each character is a "d" or a "p" with one to four dashes above or below it. The three ways a "d" can carry exactly two dashes are the targets. Everything else is a distractor.1
Distractors as described for the current form.1 Another source lists "p" with up to four dashes.2
Work left to right. Tap every d with two dashes.
Each row runs on its own clock and moves to the next row with no pause, as in the original test.2 Tap a character again to unmark it. The test allows 15 or 20 seconds per row depending on the expected level of performance, so you can choose.1
Randomly generated rows in the d2 format. This isn't the test sheet and isn't normed.
Speed is the score to trust
A 2017 study of how the d2 is scored found that the reliability of the error score comes almost entirely from missed targets. Wrong marks were entirely unreliable, and measures of how much speed varied weren't reliable enough either.5
Its conclusion: speed, the number of items worked through per row, is clearly the best measure of sustained attention in practice. Brickenkamp himself suggested an error-corrected speed score.5
One sheet, 658 characters, 4 minutes 40 seconds
From paper sheet to screen, and into clinical trials
References
- [1]Disentangling the contributions of repeating targets, distractors, and stimulus positions to practice benefits in d2-like tests of attention (2023). Collabra: Psychology, 9(1). University of California Press.online.ucpress.edu
- [2]Is the d2 Test of Attention Rasch scalable? Analysis with the Rasch Poisson Counts Model (2018). ResearchGate.researchgate.net
- [3]Description of d2: assessing attention and concentration. Scribd.scribd.com
- [4]Brickenkamp, R. Test d2 – Aufmerksamkeits-Belastungs-Test. ResearchGate record.researchgate.net
- [5]Steinborn, M. B., et al. (2017). Methodology of performance scoring in the d2 sustained-attention test: cumulative-reliability functions and practical guidelines. Psychological Assessment. University of Würzburg (PDF).psychologie.uni-wuerzburg.de (PDF)
- [6]Cognitive enhancement in bipolar disorder (NCT00597896), outcome: change in d2 Test of Attention. ClinicalTrials.gov.clinicaltrials.gov
- [7]Acute effects of cell phone exposure on immediate attention levels and concentration of emergency physicians (NCT03239925). ClinicalTrials.gov.clinicaltrials.gov
- [8]Brickenkamp, R. The d2 test of attention (manual, viii + 72 p.). Internet Archive.archive.org
- [9]Toward finding and supporting struggling students in a programming course with an early warning system (2024). arXiv:2402.01709.arxiv.org/pdf/2402.01709
Related historical tests
Its Digit Symbol subtest is also a timed paper-and-pencil task where speed matters. One study treated its comparison with a Wechsler intelligence scale as evidence that the d2 measures something different from IQ.
The WISC's Coding subtest is timed symbol work much like a cancellation task. The d2 isolates that kind of attention and speed as a test of its own.
Another test built from non-verbal symbols with strict time limits. It measures reasoning, whereas the d2 measures how long you can keep scanning accurately.
Recruits were told to finish each Beta test as quickly as possible. The d2 makes speed the main score, fixing the time per row and counting what you get through.
Another paper-and-pencil task where impulsive errors matter. Porteus looked at planning ahead; the d2 at staying accurate under time pressure.
Hamilton's scale became a standard outcome in drug trials. The d2 has been used the same way, with change in attention as the primary outcome.