Working Memory
Digit Span Test
Assess verbal working-memory span with adaptive forward and backward digit recall in the browser.
5-7 minUntimed
Free to start: 10 free participants per account, then $0.99 per participant for academic research, or any yearly plan. Try it here first, with no account.
- Papers, 2021 to 2025
- 2,755
- Evidence grade
- A
- Registered clinical studies
- 1,629
What it measures
Measures verbal working memory capacity by asking participants to recall sequences of digits in forward and backward order.
Constructs
- Verbal working memory capacity
- Phonological loop
- Mental manipulation (backward)
- Serial recall
- Executive working memory (backward)
Research uses
- Intellectual disability assessment
- Dementia screening (WAIS subtest)
- Learning disability evaluation
- Traumatic brain injury assessment
- Pre/post intervention measurement
How the paradigm works
The Digit Span Test measures verbal working memory capacity using an adaptive staircase procedure. In the forward phase, participants view a sequence of digits (1-9) presented one at a time and must type them back in order. In the backward phase, they must recall the digits in reverse order.
More about the paradigm
The test starts at a span of 3 digits and increases by one digit after successful recall. Two trials are given at each span length; the participant must pass at least one to advance. The test terminates when both trials at a span length are failed, or when the maximum span (9) is reached.
Forward span primarily taps the phonological loop component of working memory (passive maintenance and rehearsal). Backward span additionally requires mental manipulation and reordering, engaging executive working memory processes. The forward-backward difference isolates executive contribution to working memory performance.
Scores
- Forward Spanscore
- Longest digit sequence correctly recalled in forward order. Primary capacity measure.
- Higher is better
- Backward Spanscore
- Longest digit sequence correctly recalled in reverse order. Null if backward phase not included.
- Higher is better
- Total Scorescore
- Forward span + backward span. Composite working memory measure.
- Higher is better
- Longest Forwardscore
- Same as forward span. Maximum sequence length achieved.
- Higher is better
- Longest Backwardscore
- Same as backward span. Maximum reverse sequence length achieved.
- Higher is better
Use and evidence
2,755 papers from 2021 to 2025 name this task in their title or abstract, up 16% compared with 2016 to 2020. That ranks it 8 of 582 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 710 |
| 2024 | 545 |
| 2023 | 580 |
| 2022 | 456 |
| 2021 | 464 |
| 2020 | 509 |
| 2019 | 468 |
| 2018 | 494 |
| 2017 | 468 |
| 2016 | 438 |
| 2015 | 408 |
| 2014 | 360 |
| 2013 | 343 |
| 2012 | 338 |
| 2011 | 262 |
| 2010 | 272 |
| 2009 | 213 |
| 2008 | 209 |
| 2007 | 167 |
| 2006 | 149 |
| 2005 | 162 |
| 2004 | 136 |
| 2003 | 129 |
| 2002 | 99 |
| 2001 | 93 |
| 2000 | 99 |
Use grade A
1,000 or more papers from 2021 to 2025.
Evidence grade A
At least 25 papers report its test-retest reliability and at least 25 registered clinical studies use it as an outcome.
- Papers on test-retest reliability
- 136
- Papers on reliability or validity
- 1,202
- Registered clinical studies using it as an outcome
- 1,629
Measured on ConductCognition
Pooled across the studies that feed our platform norms, by device group. A figure needs 50 or more people.
No pooled figure yet.
How the grades work
Use: A is 1,000 or more papers from 2021 to 2025, B 300 to 999, C 100 to 299, D 30 to 99 and E fewer than 30. Evidence: A means at least 25 papers report its test-retest reliability and at least 25 registered clinical studies use it as an outcome; B, at least 8 test-retest papers, and either 5 registered clinical studies or 150 reliability or validity papers; C, at least 2 test-retest papers, 30 reliability or validity papers or 3 registered clinical studies; D, little published measurement evidence found. The counts measure use. They include every paper that names the task in its title or abstract. Grades describe the published research on this task, not ConductCognition's version of it.
Source: ConductCognition test census 0.39.0, counted 31 October 2026 from OpenAlex and ClinicalTrials.gov.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: digit_forward and digit_backward. A recalled sequence has no meaningful chance level, so accuracy is not judged against chance; recall is untimed, so nothing can be missed. Recalling no forward sequence correctly is flagged. A hidden tab withholds the percentile.
Why these rules
A random digit sequence matches with probability 1/9 to the power of the span length, so chance is not meaningful, and a floor score can be a real result. A hidden tab lets the study, delay or response timers run without the participant, so a percentile is withheld after one.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Starting span length | 3 | 2 to 5 |
| Maximum span length | 9 | 6 to 12 |
| Include backward span | On | On or off |
Yearly plans can change settings within these limits. Free and pay-as-you-go studies use the standard settings.
Need a setting this test does not have?
Devices and languages
- Untimed test: runs on desktops, laptops, tablets and phones. Participant devices
- Languages: English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese.
- Available on: Every plan, including the free plan.
- Recruiting online? See the setup guides for Prolific, Sona Systems, CloudResearch Connect and Qualtrics.
Included in these batteries
Each battery runs this test with others in a fixed order, with standard settings.
- Working Memory and Learning Battery4 tests, 19 minutes per participant
- Older Adult Executive Speed Battery4 tests, 20 minutes per participant
- At-Home Memory Battery4 tests, 26 minutes per participant
- School-Age Battery5 tests, 33 minutes per participant
Cite and describe
Participants completed the Digit Span Test in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Wechsler, 1939; Baddeley & Hitch, 1974), with the standard settings (starting span length: 3; maximum span length: 9; include backward span: On). The main score was forward span (longest digit sequence correctly recalled in forward order).
Paradigm source: Wechsler (1939); Baddeley & Hitch (1974).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
Source papers
- Woods DL, Kishiyama MM, Yund EW, Herron TJ, Edwards B, Poliva O, Hink RF, Reed B (2011). Improving digit span assessment of short-term verbal memory. Journal of Clinical and Experimental Neuropsychology, 33(1):101-111.Paradigm source
Questions
How long does the Digit Span Test take?
About 5 to 7 minutes, as listed in the test library.
What device does a participant need?
Untimed test: runs on desktops, laptops, tablets and phones. The browser must be Chrome, Edge, Firefox or Safari.
What scores does it produce?
Forward Span, Backward Span, Total Score, Longest Forward and Longest Backward. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Digit Span Test used in research?
2,755 papers from 2021 to 2025 name it in their title or abstract, up 16% compared with 2016 to 2020. That ranks it 8 of 582 test families in the ConductCognition test census (use grade A). Source: ConductCognition test census 0.39.0, counted 31 October 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Digit Span Test have?
In the published research, 136 papers report its test-retest reliability and 1,629 registered clinical studies use it as an outcome (evidence grade A in the ConductCognition test census).
Which settings can a researcher change?
Starting span length (2 to 5), maximum span length (6 to 12) and include backward span (On or off). Settings can be changed on yearly plans; free and pay-as-you-go studies use the standard settings.
Which languages can participants use?
Participants can take this test in English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese. English is on every plan, and the other languages come with yearly plans. Have a native speaker read the machine-translated text before launch.
Is this a clinical test?
No. ConductCognition is for research use only. It runs, scores and exports the test; clinical interpretation is outside the platform.
Every test: the full test list.
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