Processing Speed
Fraction Comparison Task
Also called: fraction magnitude comparison, rational number comparison, whole number bias task
Measure fraction understanding with timed comparisons. Separate accuracy and speed for shared components, misleading whole numbers, and close or far fraction values.
3-8 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
- 8
- Evidence grade
- D
- Registered clinical studies
- 0
What it measures
Measures how accurately and quickly people compare fraction sizes. Choose the larger of two fractions with the F and J keys. Scores separate pairs with a shared numerator or denominator from pairs where larger whole-number components help or mislead, and compare close with far fraction values.
Constructs
- Fraction magnitude
- Component congruency
- Numerical processing speed
Research uses
- Mathematics education research
- Numerical cognition research
How the paradigm works
Fraction size can conflict with the sizes of its numerator and denominator. This task measures how accurately and quickly people compare rational values across four kinds of pairs: shared denominators, shared numerators, and different components that either help or mislead the comparison. Schneider and Siegler (2010) showed that adults can use fraction magnitude when component shortcuts are not consistently useful.
More about the paradigm
Our code generates proper, reduced fractions with denominators from 2 to 12. Each round contains 64 comparisons: eight in each combination of four component conditions and two magnitude-distance bands, with the larger fraction on each side equally often. Close pairs differ by at most 0.20; far pairs by at least 0.30. Eight separate pairs provide practice.
The standard is one round, with a setting for one to three. A cross appears for 500 ms, followed by the numbers for up to 6,000 ms. Participants answer with F or J on a desktop or laptop keyboard. Practice gives feedback for 800 ms; test trials give none. Accuracy is the main measure, with correct response times and condition summaries alongside it. Responses under 100 ms are counted as anticipations. Scores support research; the generated items do not use published norms or diagnostic cutoffs.
Scores
- Accuracy%
- Share of all test trials answered correctly from 100 to 6,000 ms, including missed and premature responses in the denominator.
- Higher is better
- Median Correct Response Timems
- Median time for correct answers from 100 to 6,000 ms.
- Lower is faster
- Distance Effectms
- Median correct response time for close pairs minus far pairs, with at least five correct responses per band.
- Positive means close pairs took longer
- Component Congruency Effectms
- Median correct response time for incongruent pairs minus congruent pairs, with at least five correct responses in each.
- Positive means misleading components took longer
- Component Accuracy Gap%
- Congruent minus incongruent accuracy.
- Positive means congruent pairs were more accurate
- Close Pairs Accuracy%
- Accuracy for fractions at most 0.20 apart.
- Higher is better
- Far Pairs Accuracy%
- Accuracy for fractions at least 0.30 apart.
- Higher is better
- Accuracy by Fraction Condition%
- Accuracy for shared denominators, shared numerators, congruent and incongruent components.
- Compare conditions
- Response Time by Fraction Conditionms
- Median correct response time in each fraction condition.
- Compare conditions
- Anticipationscount
- Responses under 100 ms; excluded from correct responses and response-time summaries.
- Lower is better
- Missed Responsescount
- Trials with no usable key press within 6,000 ms.
- Lower is better
- Completed Trialstrials
- Test trials shown in the selected run.
- Compare with planned trials
- Planned Trialstrials
- Number of test trials planned for the run.
- Informational
Use and evidence
8 papers from 2021 to 2025 name this task in their title or abstract. That ranks it 458 of 495 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 4 |
| 2024 | 1 |
| 2023 | 1 |
| 2022 | 2 |
| 2021 | 0 |
| 2020 | 1 |
| 2019 | 2 |
| 2018 | 1 |
| 2017 | 1 |
| 2016 | 0 |
| 2015 | 1 |
| 2014 | 2 |
| 2013 | 0 |
| 2012 | 0 |
| 2011 | 1 |
| 2010 | 0 |
| 2009 | 1 |
| 2008 | 0 |
| 2007 | 0 |
| 2006 | 0 |
| 2005 | 0 |
| 2004 | 0 |
| 2003 | 0 |
| 2002 | 0 |
| 2001 | 0 |
| 2000 | 0 |
Use grade E
Fewer than 30 papers from 2021 to 2025.
Evidence grade D
Little published measurement evidence found.
- Papers on test-retest reliability
- 0
- Papers on reliability or validity
- 1
- Registered clinical studies using it as an outcome
- 0
Note on the counts: Original generated items; research scores; no published norms..
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 0.22.0, counted 2 November 2026 from OpenAlex and ClinicalTrials.gov.
Task design
The trial sequence as the test runs in ConductCognition.
- Display
- A cross for 500 ms, then the numbers until F or J or a 6,000 ms limit. Response time starts on the frame that draws the numbers.
- Keys
- F for the larger fraction on the left; J for the larger fraction on the right.
- Trials
- 1 round of 64 test trials as standard; 1 to 3 rounds. Trial order is seeded and recorded.
- Practice
- 8 separate items with 800 ms feedback, one from each design cell. Practice items never enter the test in that run.
- Items
- Proper, reduced fractions with denominators 2 to 12. Shared denominator, shared numerator, congruent and incongruent component conditions, each with eight close and eight far pairs per round.
- Balance
- The larger fraction appears on each side four times in every eight-item condition and distance cell.
- Score
- Accuracy over all test trials. Correct response times use 100 to 6,000 ms; time contrasts need five usable correct answers in each group.
The items, trial counts and six-second limit were set for this version. Condition contrasts describe these generated items; they do not identify a unique strategy or carry the published tasks’ norms.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: fraction_comparison_test from the most complete run, with the last run winning ties. Two balanced keys, chance 50%, graded again from the saved numbers. Below chance invalidates; not above chance is flagged. One key on 90% of answers invalidates when accuracy is not above chance. An incomplete run is flagged. Missed responses and responses under 100 ms follow the timed-test rule.
Why these rules
Accuracy significantly below chance (one-sided exact test, p < .05) cannot come from guessing; it means the response mapping was reversed or the task was not followed (Slick, Sherman and Iverson 1999 treat below-chance forced-choice performance as definite response bias). Chance-level accuracy can be a real result in impaired participants, so it is only flagged. One option on at least 90% of answered trials, when the correct options are balanced and accuracy is not above chance, means the answers did not depend on the items (the task counterpart of long-string responding in surveys; Curran 2016). Missed responses and responses under 100 ms keep the platform's timed-test rule: more than max(3, 25%) missed responses or more than max(2, 20%) responses under 100 ms invalidate, and any is flagged. A response under 100 ms cannot be a reaction to the stimulus.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Rounds of 64 comparisons | 1 | 1 to 3 |
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.
- Recruiting online? See the setup guides for Prolific, Sona Systems, CloudResearch Connect and Qualtrics.
Cite and describe
Participants completed the Fraction Comparison Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Schneider and Siegler, 2010), with the standard settings (rounds of 64 comparisons: 1). The main score was accuracy (share of all test trials answered correctly from 100 to 6,000 ms, including missed and premature responses in the denominator).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Schneider, M., & Siegler, R. S. (2010). Representations of the magnitudes of fractions. Journal of Experimental Psychology: Human Perception and Performance, 36(5), 1227-1238. https://doi.org/10.1037/a0018170Fraction magnitude comparison and the role of component strategies.
Source papers
Questions
How long does the Fraction Comparison Task take?
About 3 to 8 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?
Accuracy, Median Correct Response Time, Distance Effect, Component Congruency Effect, Component Accuracy Gap, Close Pairs Accuracy, Far Pairs Accuracy, Accuracy by Fraction Condition, Response Time by Fraction Condition, Anticipations, Missed Responses, Completed Trials and Planned Trials. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Fraction Comparison Task used in research?
8 papers from 2021 to 2025 name it in their title or abstract. That ranks it 458 of 495 test families in the ConductCognition test census (use grade E). Source: ConductCognition test census 0.22.0, counted 2 November 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Fraction Comparison Task have?
In the published research, 0 papers report its test-retest reliability and 0 registered clinical studies use it as an outcome (evidence grade D in the ConductCognition test census).
Which settings can a researcher change?
Rounds of 64 comparisons (1 to 3). 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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