AGCT vs CAT-II vs CORE: Which Test Fits?

Choose AGCT for long-form, 40-minute classification-test practice; CAT-II for an adaptive 30–60-item experience with separate item timers; or CORE for a fixed 46-question general-reasoning form with back-and-next navigation. These are different testing experiences, but none should be treated as a universally “most accurate” IQ test.

Quick Comparison

Test name	Format	Question structure	Time limit	Adaptive or fixed	Skills measured	Best suited for	Result type	Test link
Army General Classification Test (AGCT) practice	Long-form online practice	150 four-choice questions; previous and next controls	40-minute overall timer	Fixed	Vocabulary/verbal, quantitative, spatial	Practicing sustained pace across a long classification-style form	Section results plus site-specific overall and percentile estimates based on the current 105-item scoring subset	Take the AGCT
CAT-II IQ Test	Computer-adaptive assessment	30–60 final-answer items selected from a 60-item pool	60 or 75 seconds per item; no fixed total duration	Adaptive	Quantitative knowledge, verbal comprehension, fluid reasoning	Experiencing item-level adaptation and timed decisions	Model-based IQ-style and percentile estimates, category percentages, precision, and estimated standard error	Take CAT-II
CORE Cognitive Reasoning Evaluation context	Informational page opening the shared CognitiveIndex IQ Assessment	46 four-choice questions; previous and next controls	30-minute overall timer	Fixed	Abstract/logical, numerical, verbal, and spatial-orientation reasoning	Trying a shorter broad fixed form with review controls	Generic `iq` result with correct-answer categories and internal IQ-style and percentile estimates	Review CORE

All three are informational online assessments. The repository does not contain evidence that their displayed estimates are interchangeable with a professionally administered IQ score.

The Biggest Difference: Fixed Form vs. Adaptive Path

AGCT and the assessment linked from CORE are fixed forms. Users receive the same planned question structure, and both interfaces allow earlier questions to be revisited while time remains.

CAT-II works differently. It updates an ability estimate after each response and selects another unused item expected to be useful near that estimate while balancing content coverage. Answers are final, paths can differ, and the test can end anywhere from 30 to 60 administered items.

If you prefer seeing the full structure and revisiting questions, choose a fixed form. If you want to experience how adaptive item selection changes the sequence, choose CAT-II.

Choose AGCT If…

AGCT is the best fit among these options when you want:

A long test that makes overall pacing important
One 40-minute limit rather than an individual timer on every item
A mix of vocabulary, practical mathematics, and spatial reasoning
Experience with a classification-test style
The ability to move backward and forward before submission

There is an important limitation. The CognitiveIndex AGCT presents 150 questions, but its current report uses a 105-item subset. The reason for that subset is not documented in the repository. Its output should therefore be interpreted as a result from this particular practice form, not an official historical AGCT score.

Read how CognitiveIndex AGCT scores work before comparing the result with another source.

Choose CAT-II If…

CAT-II is the better fit when you want:

A question path that responds to earlier performance
A test that may stop after 30 items or continue to 60
Separate 60- or 75-second decisions
Quantitative, verbal, and fluid-reasoning feedback
A report that includes a model-based precision value and estimated standard error

CAT-II is not necessarily easier because it can be shorter. Adaptive selection tries to keep the items informative, and the inability to revisit an answer can make the session feel more demanding.

The result is an internal model-based estimate. The code implements adaptive selection and scoring, but repository evidence does not establish independent norms or clinical validity. Learn how CAT-II adaptive testing works.

Choose CORE If…

CORE is useful when you want:

A fixed 46-question mixed-reasoning form
A 30-minute overall timer
Previous and next controls
A shorter fixed experience than AGCT
Broad practice across logical, numerical, verbal, and limited spatial-orientation problems

CORE requires especially clear naming. /core is an informational context, not a separate executable test identity. Its call to action opens the shared CognitiveIndex IQ Assessment, stores the generic iq test type, and uses the generic IQ result page. The current GET practice page also leads to that same underlying flow.

Choose CORE for the context and fixed-form experience described on its page—not because it provides a separate CORE question bank, norm, or score.

For broader background, read what a “core IQ test” usually means.

Which Test Is Most Accurate?

The repository does not support declaring one universally most accurate. Accuracy is not determined by length or adaptive delivery alone. It depends on the specific claim being made and evidence such as:

Representative norms
Reliability and measurement precision
Validity for the intended interpretation
Standardized administration
Item quality and content coverage
Appropriate score ceilings and floors
Independent comparison with relevant instruments

CAT-II exposes model-based precision, but that number describes its implemented algorithm. AGCT provides more items, but 45 presented responses do not affect its report. CORE uses a shorter fixed form and a generic internal conversion. None of those facts alone proves superiority.

For a clinical diagnosis, school placement, disability documentation, or another high-stakes use, choose a qualified professional rather than one of these online estimates.

Practical Decision Path

Want a long, fixed, historically themed practice form? Start with AGCT.
Want the question sequence to adapt after each response? Start with CAT-II.
Want a 30-minute fixed mixed-reasoning form with review controls? Read the CORE context.
Need an accepted result for diagnosis, eligibility, or documentation? Do not use these online forms for that decision; consult the relevant qualified professional or institution.

The complete test catalog also includes CRI, APT, CAT-II, AGCT, and other available formats.

Frequently Asked Questions

Is CAT-II shorter than AGCT?

Usually, but its exact duration varies. CAT-II administers 30–60 individually timed items. AGCT presents 150 questions under a 40-minute overall timer.

Is CORE a separate test from the CognitiveIndex IQ Assessment?

No. CORE is an informational context that launches the shared 46-question iq assessment and its generic IQ result flow.

Can I compare scores across AGCT, CAT-II, and CORE?

Only as results from their respective CognitiveIndex forms. Their item structures and scoring methods differ, and the repository does not establish that the displayed estimates are directly interchangeable.

Which test allows me to change earlier answers?

AGCT and the fixed assessment linked from CORE provide previous and next controls. CAT-II answers are final because each response affects the next selected item.

Which test should I use for a clinical or school decision?

None of these online forms should be used for diagnosis, school eligibility, or other high-stakes decisions. Use an appropriately standardized assessment administered and interpreted by a qualified professional.

Sources

Standards for Educational and Psychological Testing, AERA, APA, and NCME.
ITC/ATP Guidelines for Technology-Based Assessment, International Test Commission and Association of Test Publishers.
Overview of Psychological Testing, National Academies via NCBI Bookshelf.

AGCT vs. CAT-II vs. CORE: Which Test Should You Take?