Attention
Letter String Report Task
Also called: visual attention span task, global report, whole and partial letter report
Measure how many letters a person takes in at once. Five letters flash briefly, then participants report the whole string or one marked letter.
6-9 minTimed: desktop or laptop with a mouse or trackpad
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
- 47
- Evidence grade
- C
- Registered clinical studies
- 5
What it measures
Measure how many letters a person takes in from one brief string. Five consonants flash for 200 ms. Participants report all the letters they saw, then a single letter at a marked position. Whole and partial reports measure visual attention span, studied in reading research.
Constructs
- Visual attention span
- Parallel letter processing
Research uses
- Reading research
- Developmental dyslexia research
- Within-study group comparison
How the paradigm works
Visual attention span describes how many letters can be taken in together from a brief display. This task presents original five-consonant strings for 200 ms, followed by a report of all seen letters or a single position marked after the display. Whole reports score letter identities regardless of order; partial reports score the marked position.
More about the paradigm
The standard session has 20 whole and 50 partial reports after four and five practice trials. Each position is cued ten times in seeded order. Reports are typed without a deadline, and display durations are recorded from screen frames. Whole-report letters are the primary score; partial accuracy times five estimates available letters across the string. Position scores show how report accuracy varies along the row.
Scores
- Whole-report Lettersitems
- Mean correctly reported identities per whole display, regardless of order.
- Higher means more letters reported.
- Partial-report Lettersitems
- Share of cued letters correct multiplied by five.
- Estimated letters available across the string.
- Cued-letter Accuracy%
- Share of cued letters correctly reported.
- Higher means more cued letters correct.
- Position 1 Accuracy%
- Accuracy when position 1 from the left is cued.
- Compare positions within a study.
- Position 2 Accuracy%
- Accuracy when position 2 from the left is cued.
- Compare positions within a study.
- Position 3 Accuracy%
- Accuracy when position 3 from the left is cued.
- Compare positions within a study.
- Position 4 Accuracy%
- Accuracy when position 4 from the left is cued.
- Compare positions within a study.
- Position 5 Accuracy%
- Accuracy when position 5 from the left is cued.
- Compare positions within a study.
- Report Precision%
- Correct letters divided by all letters submitted.
- Low precision indicates many reported letters were absent.
- Median Report Timems
- Time from the report prompt to submission, excluding submissions under 100 ms.
- Descriptive; speed is not the goal.
- Anticipationscount
- Premature keys and submissions under 100 ms.
- Premature keys are not accepted.
- Frame Intervalms
- Median measured frame interval.
- Describes the screen timing.
- Displays on Time%
- Share with measured exposure and mask within one frame of plan and no display interruption.
- Below 90% is flagged for review.
- Planned Reportscount
- Number of scored reports planned.
- Compare with completed reports.
- Completed Reportscount
- Number of valid report rows in the selected run.
- Blank reports count; missing rows do not.
Use and evidence
47 papers from 2021 to 2025 name this task in their title or abstract, down 15% compared with 2016 to 2020. That ranks it 370 of 582 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 10 |
| 2024 | 14 |
| 2023 | 5 |
| 2022 | 10 |
| 2021 | 8 |
| 2020 | 15 |
| 2019 | 14 |
| 2018 | 10 |
| 2017 | 5 |
| 2016 | 11 |
| 2015 | 9 |
| 2014 | 8 |
| 2013 | 11 |
| 2012 | 9 |
| 2011 | 2 |
| 2010 | 2 |
| 2009 | 1 |
| 2008 | 1 |
| 2007 | 8 |
| 2006 | 2 |
| 2005 | 1 |
| 2004 | 1 |
| 2003 | 0 |
| 2002 | 0 |
| 2001 | 1 |
| 2000 | 0 |
Use grade D
30 to 99 papers from 2021 to 2025.
Evidence grade C
At least 2 test-retest papers, 30 reliability or validity papers or 3 registered clinical studies.
- Papers on test-retest reliability
- 0
- Papers on reliability or validity
- 5
- Registered clinical studies using it as an outcome
- 5
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 8 November 2026 from OpenAlex and ClinicalTrials.gov.
Task design
The trial sequence as the test runs in ConductCognition.
- Display
- Five different uppercase consonants in one row, 30 px letters spaced 48 px apart on a 300 by 220 px dark panel. Strings are drawn from B, D, F, H, L, M, P, R, S and T.
- Timing
- A central dot for 500 ms, then the letters for 200 ms. In partial report, an arrow appears below one position as the letters disappear. There is no mask or cue delay. Actual display times are recorded.
- Answer
- Type the letters in any order, then press Enter or choose Done. Report only letters you are fairly sure you saw. A blank report is allowed. Backspace removes the last letter. Partial reports ask for only the marked letter.
- Length
- 20 whole reports followed by 50 partial reports, with each of the five positions cued 10 times. The setting allows 6 to 16 reports per position, with twice that many whole reports. A break follows every 28 scored trials within a part.
- Practice
- Four whole reports and five partial reports, each followed by the letters and a correct-letter count for 1,000 ms.
- Scores
- Mean letters correctly reported in whole report, partial-report accuracy times five, accuracy at each position, and the share of reported letters that were correct.
This version uses typed reports and original strings, with no published diagnostic cutoff. The same Latin consonants appear in every language. Compare participants with similar familiarity with these letters; the test cannot check gaze. Scores support research on visual attention and reading.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scores use the completed run's letter reports. A blank report means no letters were seen. Low recall is part of the measure, so accuracy and repeated answers do not invalidate a run. Reports submitted under 200 ms on at least half the trials invalidate. Premature keys are counted and ignored. Missing reports, fewer than 90% of displays within one frame of plan, or report precision below 80% are flagged for review. Display interruptions are recorded.
Why these rules
Report accuracy depends on brief exposure and memory. A person may correctly report no letters at short exposures; this is not an omission. Display timing is needed to interpret letter report performance.
No percentile. Scores and quality flags only.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Reports at each position | 10 | 6 to 16 |
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
- Timed test: participants need a desktop or laptop with a mouse or trackpad. Participant devices
- Languages: English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese.
- Available on: Every plan, including the free plan.
- No percentile. Scores and quality flags only. How norms work
- Recruiting online? See the setup guides for Prolific, Sona Systems, CloudResearch Connect and Qualtrics.
Cite and describe
Participants completed the Letter String Report Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Bosse, Tainturier and Valdois, 2007), with the standard settings (reports at each position: 10). The main score was whole-report letters (mean correctly reported identities per whole display, regardless of order).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Bosse, M.-L., Tainturier, M. J., & Valdois, S. (2007). Developmental dyslexia: The visual attention span deficit hypothesis. Cognition, 104(2), 198-230. https://doi.org/10.1016/j.cognition.2006.05.009
Source papers
Questions
How long does the Letter String Report Task take?
About 6 to 9 minutes, as listed in the test library.
What device does a participant need?
Timed test: participants need a desktop or laptop with a mouse or trackpad. The browser must be Chrome, Edge, Firefox or Safari.
What scores does it produce?
Whole-report Letters, Partial-report Letters, Cued-letter Accuracy, Position 1 Accuracy, Position 2 Accuracy, Position 3 Accuracy, Position 4 Accuracy, Position 5 Accuracy, Report Precision, Median Report Time, Anticipations, Frame Interval, Displays on Time, Planned Reports and Completed Reports. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Letter String Report Task used in research?
47 papers from 2021 to 2025 name it in their title or abstract, down 15% compared with 2016 to 2020. That ranks it 370 of 582 test families in the ConductCognition test census (use grade D). Source: ConductCognition test census 0.39.0, counted 8 November 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Letter String Report Task have?
In the published research, 0 papers report its test-retest reliability and 5 registered clinical studies use it as an outcome (evidence grade C in the ConductCognition test census).
Does it report a percentile?
No. Scores and quality flags only.
Which settings can a researcher change?
Reports at each position (6 to 16). 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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