Homeschool Testing Options for Washington State: CAT, Iowa, Stanford, and Woodcock-Johnson Compared

Once you decide to go the standardized test route for Washington's annual assessment, the next question is which test. The CAT, Iowa Tests, Stanford Achievement Test, and Woodcock-Johnson all circulate in Washington homeschool communities, and families often pick based on what they have heard from others rather than what actually fits their situation. Here is a side-by-side breakdown to help you choose deliberately.

What Washington's Law Actually Requires from the Test

Washington law under RCW 28A.200.010 requires that the standardized test be administered by a qualified person — meaning a Washington State certificated teacher or someone meeting the same qualification requirements. It does not specify which test, which publisher, or which grade level. The test must be nationally normed and administered appropriately, but the specific instrument is your choice.

This is meaningful because it means there is no official Washington State approved test list. Any reputable, nationally normed achievement test administered by a qualified person satisfies the requirement. The tests below are common choices among Washington families, not a prescribed state menu.

The California Achievement Test (CAT)

The California Achievement Test, specifically the CAT/5 (also sold under the name "CAT Survey Plus" in some testing services), is one of the most commonly used homeschool assessments nationally and in Washington.

What it tests: Reading, language arts, and mathematics. Some versions include science, social studies, and reference skills. The CAT is a multiple-choice group test, so it assesses recognition and selection rather than open-ended writing or verbal explanation.

Format: Untimed (in most homeschool versions). Students work through questions at their own pace, which removes a significant source of testing anxiety. The CAT is available at specific grade levels from kindergarten through high school.

Administration in Washington: Several Washington-based testing services and certificated teachers administer the CAT. It is also offered through national homeschool testing services that work with Washington families and meet the qualified administrator requirement.

Strengths: The untimed format suits students who need more processing time. It is widely accepted and produces normed score reports that are clearly legible to community college admissions offices and Running Start verification processes.

Limitations: Multiple-choice format does not capture writing quality, oral expression, or applied problem-solving. If your student excels in verbal or hands-on learning, the CAT may underrepresent their actual capability.

The Iowa Tests of Basic Skills / Iowa Assessments (ITBS)

The Iowa Tests of Basic Skills — now marketed as the Iowa Assessments — are published by Riverside and have been used in both public school systems and homeschool assessments for decades.

What it tests: Reading, language arts, mathematics, science, and social studies across most grade levels. The Iowa Tests include a listening component in lower elementary grades and expand to include separate vocabulary, reading comprehension, language mechanics, and math problem-solving sections as grade levels increase.

Format: Timed, with strict time limits per subtest. This is the most significant structural difference from the CAT. Students who perform poorly under time pressure may score below their actual knowledge level.

Administration in Washington: FLO (Family Learning Organization) offers the Iowa Tests as their standardized testing option alongside their non-test evaluation services. Other Washington certificated teachers and testing services also administer Iowa.

Strengths: The Iowa Tests have deep institutional recognition. Community colleges, the UW system, and Running Start administrators have seen Iowa scores for decades and understand exactly what they mean. The detailed subtest structure gives you specific diagnostic information about where a student is strong or struggling.

Limitations: Timed format. The strict time limits affect students with processing differences, anxiety, or who simply think more deliberately. If your student consistently needs more time than their public-schooled peers, the untimed CAT or a non-test evaluation may be a better fit.

The Stanford Achievement Test (SAT-10)

The Stanford Achievement Test, Tenth Edition (SAT-10), should not be confused with the SAT college entrance exam. The SAT-10 is an achievement battery published by Pearson and normed against a national sample of students.

What it tests: Reading, mathematics, language, science, social studies, and listening (in elementary versions). The SAT-10 has a reputation for being slightly more challenging than comparable tests at the same grade level, particularly in reading comprehension and mathematics reasoning.

Format: Timed. Similar to Iowa, the SAT-10 uses strict time limits per subtest.

Administration in Washington: The SAT-10 is available through Washington certificated teachers and some national homeschool testing services. It is less universally available than the Iowa or CAT because fewer local administrators are trained on it, so you may have a smaller pool of administrators to choose from.

Strengths: The SAT-10's rigor makes high scores particularly meaningful for Running Start and college admissions documentation. If a student performs well on the SAT-10, it is a strong signal.

Limitations: Its relative difficulty and timed format can be discouraging for students who perform closer to grade-level expectations. For families whose primary goal is annual assessment compliance rather than competitive academic signaling, this level of rigor may not be necessary.

The Woodcock-Johnson Tests of Achievement (WJ IV)

The Woodcock-Johnson Tests of Achievement, Fourth Edition (WJ IV) is a fundamentally different type of assessment from the three tests above. It is an individually administered diagnostic battery, not a group-administered multiple-choice test.

What it tests: Reading (including phonological awareness, fluency, and comprehension), written language, mathematics, and academic knowledge — science, social studies, and humanities. The WJ IV can be administered as a complete battery or with selected clusters depending on what information the evaluator needs.

Format: One-on-one, administered by a trained examiner. The student responds verbally, writes answers, or points to responses depending on the subtest. There are no multiple-choice bubbles. The individual format allows the examiner to observe how the student approaches problems, not just whether they get the right answer.

Administration in Washington: The WJ IV must be administered by a trained examiner — typically an educational psychologist, a certificated teacher with specific WJ training, or a learning specialist. Not every certificated teacher who offers homeschool assessments is trained on the Woodcock-Johnson. You need to verify the examiner's specific qualifications.

Strengths: The WJ IV is the strongest assessment for families with neurodivergent learners, students with learning differences, or families who want diagnostic information beyond simple grade-level scores. An individual assessment can distinguish between a student who struggles with all reading tasks and one who has strong comprehension but slow decoding speed. That specificity is genuinely useful for curriculum planning and for documenting a student's progress in a way that captures what they actually know.

Limitations: Cost. Woodcock-Johnson administrations typically run $150 to $400 depending on the examiner and what clusters are administered. For families whose goal is straightforward annual assessment compliance, this level of investment is hard to justify over a $40 to $80 CAT or Iowa administration.

How to Choose

Choose the CAT if: Your student tends to test anxiously, needs untimed conditions, or you want a low-friction annual compliance check with reliable results.

Choose the Iowa Tests if: You want detailed diagnostic subscores, your student handles timed tests well, and you value the institutional name recognition for Running Start or university admissions.

Choose the Stanford Achievement Test if: Your student is a strong academic performer and you want a rigorous benchmark that carries weight for competitive college applications.

Choose the Woodcock-Johnson if: Your student has a learning difference, a processing disorder, or you need genuinely diagnostic information to guide curriculum — and you are willing to pay for that depth.

For most Washington families doing annual assessment compliance, the CAT or Iowa is sufficient. The non-test evaluation path through FLO or a private certificated teacher is worth considering if your child's learning style does not lend itself to standardized tests or if you are using an approach like unschooling where a multiple-choice test is a genuinely poor measure of what the child knows.

What Test Results Tell You — and What They Don't

One thing standardized test scores do not do under Washington law: they do not need to reach any minimum threshold. There is no passing score. A student who tests at the 25th percentile has satisfied the annual assessment requirement just as completely as one who tests at the 90th percentile.

What test scores can do is give you a longitudinal comparison of the student's own progress from year to year, provide documentation for Running Start eligibility verification, and offer a reference point when applying to universities that ask for homeschool academic documentation.

For high school students specifically, the annual test score is one component of a broader academic record. The Washington Portfolio and Assessment Templates toolkit at /us/washington/portfolio includes transcript templates, a Running Start readiness checklist, and the crosswalk matrix for mapping coursework to Washington's required subjects — the documentation infrastructure that surrounds and contextualizes the annual test score for admissions purposes.

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