ConductCognition
PlatformTestsDataPricingGuidesOffline
Log InStart Free
  1. Home
  2. /Data
  3. /Clinical studies

Data

Cognitive tests in 16,245 registered clinical studies

Every study on ClinicalTrials.gov that names a cognitive test from the census in an outcome measure: which tests trials use, for which conditions, and how that has changed.

Registered studies name a test from the census in an outcome measure
16,245
Of those, studies that name one in a primary outcome
6,735
See the tests
Studies led by an industry sponsor
1,629

Studies by start year

Each study counted once, however many tests it names. 2026 is partly planned starts.
05001,0001,5002000: 12 studies, 5 with a test as a primary outcome20002001: 13 studies, 5 with a test as a primary outcome2002: 36 studies, 20 with a test as a primary outcome2003: 52 studies, 22 with a test as a primary outcome2004: 63 studies, 29 with a test as a primary outcome2005: 69 studies, 35 with a test as a primary outcome20052006: 91 studies, 36 with a test as a primary outcome2007: 131 studies, 52 with a test as a primary outcome2008: 159 studies, 68 with a test as a primary outcome2009: 198 studies, 91 with a test as a primary outcome2010: 235 studies, 101 with a test as a primary outcome20102011: 287 studies, 119 with a test as a primary outcome2012: 323 studies, 148 with a test as a primary outcome2013: 435 studies, 192 with a test as a primary outcome2014: 542 studies, 211 with a test as a primary outcome2015: 598 studies, 255 with a test as a primary outcome20152016: 716 studies, 293 with a test as a primary outcome2017: 847 studies, 318 with a test as a primary outcome2018: 885 studies, 365 with a test as a primary outcome2019: 1,069 studies, 478 with a test as a primary outcome2020: 927 studies, 390 with a test as a primary outcome20202021: 1,259 studies, 558 with a test as a primary outcome2022: 1,263 studies, 509 with a test as a primary outcome2023: 1,402 studies, 577 with a test as a primary outcome2024: 1,511 studies, 655 with a test as a primary outcome2025: 1,574 studies, 610 with a test as a primary outcome20252026: 1,429 studies, 553 with a test as a primary outcome

A test as a primary outcomeOnly in secondary or other outcomes

Show as a table
Registered studies by start year
Start yearStudiesA test as a primary outcome
2000125
2001135
20023620
20035222
20046329
20056935
20069136
200713152
200815968
200919891
2010235101
2011287119
2012323148
2013435192
2014542211
2015598255
2016716293
2017847318
2018885365
20191,069478
2020927390
20211,259558
20221,263509
20231,402577
20241,511655
20251,574610
20261,429553

Not shown: 23 studies that started before 2000 and 90 planned to start after 2026.

Tests most used as a primary outcome

The 20 tests in the library most often named in a primary outcome. Choose a condition to rank within it.
  1. 1Stroop Color-Word Test785 as a primary outcome, of 1,929 studies
  2. 2Verbal Learning711 as a primary outcome, of 1,832 studies
  3. 3Trail Making Test A and Trail Making Test B709 as a primary outcome, of 2,293 studies
  4. 4Verbal Fluency640 as a primary outcome, of 1,745 studies
  5. 5Digit Span Test603 as a primary outcome, of 1,629 studies
  6. 6Symbol Coding451 as a primary outcome, of 1,457 studies
  7. 71-Back Task and 2-Back Task381 as a primary outcome, of 790 studies
  8. 8Go/No-Go Task309 as a primary outcome, of 702 studies
  9. 9Continuous Performance Test265 as a primary outcome, of 638 studies
  10. 10Category Fluency232 as a primary outcome, of 623 studies
  11. 11Picture Naming Test201 as a primary outcome, of 466 studies
  12. 12Eriksen Flanker Task177 as a primary outcome, of 334 studies
  13. 13Psychomotor Vigilance Task154 as a primary outcome, of 395 studies
  14. 14Stop-Signal Task147 as a primary outcome, of 321 studies
  15. 15Paced Visual Serial Addition Test140 as a primary outcome, of 337 studies
  16. 16Card Sorting Test (Berg)139 as a primary outcome, of 411 studies
  17. 17Task Switching Test132 as a primary outcome, of 334 studies
  18. 18Short Story Recall129 as a primary outcome, of 315 studies
  19. 19Choice Reaction Time109 as a primary outcome, of 270 studies
  20. 20Complex Figure Copy and Recall107 as a primary outcome, of 276 studies

The list covers the library's tests. Clinician-administered screening tests outside the library are counted in the totals but not listed here.

Conditions and phases

Each study counted once. A study can fall in more than one condition group.

By condition

  • Dementia and Alzheimer's1,671 studies, 659 as a primary outcome
  • Depression and bipolar disorder1,240 studies, 463 as a primary outcome
  • Stroke1,230 studies, 396 as a primary outcome
  • Parkinson's disease891 studies, 276 as a primary outcome
  • Mild cognitive impairment823 studies, 483 as a primary outcome
  • Cancer754 studies, 271 as a primary outcome
  • Healthy volunteers649 studies, 349 as a primary outcome
  • Schizophrenia and psychosis638 studies, 270 as a primary outcome
  • Multiple sclerosis609 studies, 196 as a primary outcome
  • Brain injury and concussion444 studies, 229 as a primary outcome
  • ADHD357 studies, 185 as a primary outcome
  • Other conditions7,971 studies, 3,423 as a primary outcome

By phase

  • Early phase 1220 studies, 100 as a primary outcome
  • Phase 1517 studies, 202 as a primary outcome
  • Phase 1/2297 studies, 99 as a primary outcome
  • Phase 21,378 studies, 397 as a primary outcome
  • Phase 2/3162 studies, 46 as a primary outcome
  • Phase 3645 studies, 148 as a primary outcome
  • Phase 4690 studies, 263 as a primary outcome
  • Not applicable9,756 studies, 4,273 as a primary outcome
  • Observational2,578 studies, 1,207 as a primary outcome
  • Not given2 studies, 0 as a primary outcome

Lead sponsor: industry 1,629, NIH 76, other 14,540. Interventional 13,667, observational 2,578.

A test as a primary outcomeOnly in secondary or other outcomes

How the studies are counted

For each test family, the census runs ClinicalTrials.gov's own outcome search for the family's names and reads every study first posted by the day the family was counted. These studies were read on 8 November 2026. Each study counts once here, however many tests it names; the table on the main page counts it once for each test.

The census adds two things to each record and changes nothing in it: which outcome list names the test (primary, then secondary, then other), and the condition groups, matched on the study's condition names and MeSH terms. For about 2% of matches the registry's search found wording a plain check could not place; those studies count, but in no outcome list.

Source: ClinicalTrials.gov, a database of the U.S. National Library of Medicine. Every study line is in the download on the main page.

More on use and evidence

  • Test-retest evidenceWhich tests have their reliability over time on record, and which well-used tests lack it.
  • Reliability and validity evidencePapers on each test's reliability, validity and norms, set against how much it is used.
  • Every test, every measureThe full table, with grades, papers per year and a download.

Plan a trial's cognitive outcomes

Choose tests with a record in registered studies, and run them in a browser at every site.

Start free
ConductCognition

Hosted browser-native cognitive testing for academic and commercial research workflows.

A product of ConductScience, Inc.

New tests and features, about once a month. Unsubscribe at any time.

Tests

  • All cognitive tests
  • Use and evidence
  • Test norms
  • Trail Making Test
  • N-Back Task
  • Automated scoring
  • Study design
  • New tests by email

Guides

  • Recruitment setup
  • Participant devices
  • Prolific
  • Sona Systems
  • CloudResearch Connect
  • Qualtrics

Use cases

  • Student participant pools
  • Aging and dementia research
  • Clinical trials
  • US clinical research
  • Remote testing

Compare and buy

  • Pricing
  • Compare platforms
  • Offline edition
  • FAQ

Trust

  • Study Quality Monitor
  • HIPAA-ready testing
  • Data export
  • Privacy Policy
  • Terms of Use
  • Data Policy

Company

  • ConductScience
  • Affiliate Program
© 2026 ConductScience, Inc. Research use only.