CogAT vs NNAT vs NGAT: how the three gifted screening tests differ

How do the CogAT, NNAT and NGAT compare at a glance?

Sources: CogAT — Riverside Insights CogAT overview brochure, Riverside help: Types of Scores. NNAT3 — Pearson NNAT3 product page, Pearson NNAT3 Manual, Levels A–D. NGAT — MHS overview, official NGAT FAQ, MHS Help Center: Administer the test.

What does the CogAT measure?

Riverside Insights describes the Cognitive Abilities Test as a measure of general, abstract reasoning in three batteries: Verbal, Quantitative and Figural (Nonverbal). Each battery has three subtests. For kindergarten through grade 2 (Levels 5/6–8) the nine are Picture Analogies, Sentence Completion and Picture Classification; Number Analogies, Number Puzzles and Number Series; and Figure Matrices, Paper Folding and Figure Classification. From Level 9 (grade 3) the Verbal and Quantitative items become text-based, such as Verbal Analogies with words.

Riverside’s brochure times each subtest at roughly 10–15 minutes for K–2 and 10 minutes from grade 3. Its Screening Form, built from the Verbal or Picture Analogies, Number Analogies and Figure Matrices subtests, takes about 30 minutes. Schools can give it on paper or online. Riverside promotes universal screening with the CogAT and reports battery scores, composites and, for the complete battery, an Ability Profile used for differentiated instruction (source).

What does the NNAT3 measure?

Pearson’s Naglieri Nonverbal Ability Test, Third Edition is a single test of 48 multiple-choice figure items for kindergarten through grade 12, with 30 minutes of testing time. It uses shapes and pictorial directions only. Pearson presents it as a way to identify gifted students, including English learners and twice-exceptional students, without spoken or written language (source).

The test has seven levels. In the lower levels, A is the kindergarten level, B and C serve grades 1 and 2, and D covers grades 3–4; each of these four has two parallel forms. Easy items show a design with a missing piece; harder ones are grids whose figures change in several ways at once. Scores are age-based: the Naglieri Ability Index (40–160), percentile rank, stanine and normal curve equivalent (source).

What does the NGAT measure?

The Naglieri General Ability Tests from MHS, by Jack A. Naglieri, Dina Brulles and Kimberly Lansdowne, are three separate tests. Naglieri–Verbal asks which of six pictures does not share a concept, Naglieri–Nonverbal uses shape matrices and Naglieri–Quantitative uses relationships among numbers. MHS says the suite is designed to minimize the influence of culture, language, economic background and academic knowledge (source).

Each test has 40 questions, one per screen, with a limit of 30 minutes in kindergarten through grade 2 and 35 minutes in grades 3–9; students complete three sample questions first (source). The tests are given online. Each test yields one total standard score (average 100, SD 15) and no subscores, and an individual parent report is available in English and Spanish (source).

How do school districts use these tests?

All three publishers position their test for gifted and talented identification, and all three allow screening of whole grades. What differs is the content: a district that wants separate verbal and quantitative information picks a test with those parts (CogAT or NGAT); a district focused on language-light screening may choose a nonverbal measure (NNAT3, or the NGAT Nonverbal test on its own). Districts also switch tests over time.

One example: Fairfax County Public Schools in Virginia uses the online NGAT for group assessment in grades 2–7, offers the paper CogAT to students whose disability or health condition requires a paper test, and tells families that students are not expected to prepare as they would for an achievement test (source). Your own district’s web page or gifted coordinator is the only reliable answer for your child.

Can you compare scores across the three tests?

Not number for number. The CogAT Standard Age Score and the NNAT3 Naglieri Ability Index share a mean of 100 and a standard deviation of 16, while the NGAT standard score uses 15. The norm groups differ too: NNAT3 scores are by age, CogAT reports age and grade versions, and the NGAT can be scored against local or national, age or grade norms. A percentile rank only means something next to the test and norm group it came from. Districts set their own cut-offs for each.

How can a child get familiar with each format?

Every publisher stresses that these are ability tests, so the useful preparation is familiarity with the question formats and the ability to stay focused for half an hour, not memorized answers. Neobile makes one independent practice app per test, each with original questions, explanations and a parent report; none is affiliated with Riverside Insights, Pearson or MHS, and none gives an official score.

Original practice questions in the browser: CogAT kindergarten, NNAT Levels A–C, NGAT K–5.