California Achievement Test for Homeschoolers: What It Is and Whether You Need It

Standardized testing is one of the areas where California homeschool parents get the most contradictory advice. Some families assume testing is required. Others discover it is not required and stop thinking about it entirely. Neither of those is quite the right frame.

The California Achievement Test (CAT) is widely used among California homeschoolers — but not because the state requires it. Understanding why families use it, and whether it makes sense for your situation, requires understanding what California law actually says (and doesn't say) about assessment.

What Is the California Achievement Test?

The California Achievement Test is a nationally normed, standardized academic assessment that measures student performance in reading, language arts, mathematics, science, and social studies. It was developed by CTB/McGraw-Hill and has been used in schools since the 1920s. Despite the name, it is used across the United States and internationally — not just in California.

The CAT is not a California state assessment. It is not the same as the CAASPP (California Assessment of Student Performance and Progress), which is the state's public school testing system. The CAT is a privately administered, nationally normed test that any student can take, regardless of state or school type.

Current versions include the CAT/5 (5th edition) and the CAT/6. You will also see references to the CAT/Survey version, which is a shorter form covering core subjects.

The test is designed to be administered by parents at home. No proctor certification is required. This is one of the reasons it became popular in the homeschool community specifically — unlike some assessments that require a certified teacher to administer, the CAT can be done at the kitchen table.

Does California Require Homeschoolers to Take Standardized Tests?

No. California homeschool law does not require standardized testing under any legal pathway.

Private School Affidavit (PSA) filers — the most common route for California homeschoolers — operate as a private school. California private schools are not required to administer standardized tests to their students. There is no annual assessment requirement, no portfolio review, no evaluator sign-off. The state essentially leaves private schools (including home-based ones under a PSA) alone on this front.

Charter school ISP students — students enrolled in a charter school's independent study program are technically public school students and may be subject to the charter's own assessment requirements. Some ISPs require periodic testing or academic check-ins. This varies by school.

Credentialed home teacher families — no standardized testing requirement at the state level.

So if you are a PSA filer, testing is entirely optional. You choose whether to test, which test to use, and what to do with the results.

Why Do California Homeschoolers Use the CAT?

If testing is not required, why do so many California families use the California Achievement Test? A few reasons:

Personal benchmark. Many parents want an external, objective measure of where their child stands academically — not to satisfy the state, but for their own peace of mind. Homeschooling requires you to make a lot of curriculum decisions, and a standardized test gives you data on whether those decisions are working.

College and scholarship documentation. Homeschool students applying to competitive colleges or certain scholarships sometimes need standardized academic records beyond just parent-issued transcripts. A CAT score report from a third party adds credibility to a transcript, especially in earlier grades before SAT or ACT scores are available.

UC and CSU admissions context. PSA graduates applying to University of California and California State University campuses apply as "admission by exception," since their diplomas are parent-issued rather than from an accredited institution. Strong test scores — SAT, ACT, AP exams, or earlier standardized assessments in the record — help document academic preparation. CAT scores from middle school years can be part of that paper trail.

Identifying gaps. Some families use annual CAT testing specifically to spot weaknesses before they compound. A child who scores below grade level in a specific area — fractions, reading comprehension, written expression — gives the parent actionable information about where to shift curriculum focus.

Dual enrollment and community college prerequisites. Ed Code §48800 allows California students as young as 12 to enroll in community college courses. Some colleges ask for academic documentation beyond a parent transcript. A recent standardized test score can support that documentation.

Transitioning back to public school. If there is any possibility your child might re-enroll in a public school, having standardized test records makes grade placement conversations much smoother. Schools have no external reference for PSA students otherwise.

How to Administer the CAT at Home

Several vendors sell the CAT for home use. The most commonly used are:

Seton Testing Services — one of the most widely used by homeschool families. Offers the CAT/5 in multiple grade levels. Test materials are mailed to you, you administer it at home, and mail it back for scoring. Score reports are returned by mail or digitally.

Bayside School Services — another popular option, also offers the CAT/5. They also provide scoring and percentile reports.

BJU Press Testing — offers the CAT/6 and Stanford 10. Score reports include national percentile ranks and grade equivalents.

Christian Liberty Press — includes the CAT/5 as part of their annual assessment service, popular with families using their curriculum but available to others.

The cost typically runs between $30 and $60 depending on the vendor and grade level. Scoring is usually included in the purchase price.

What is included in a typical report:

• Raw score and national percentile rank (NPR) by subject
• Grade equivalent score
• Sometimes stanine scores or scaled scores

Grade equivalents are often misread. A 4th grader scoring "grade equivalent 7.2" in reading does not mean the student should move to 7th grade reading — it means the student performed as well as an average 7th grader would on 4th grade content. Use grade equivalents as one data point, not a placement decision.

How It Compares to Other Homeschool Assessments

The CAT is not the only option, and for some families it is not the best option.

Stanford 10 (Stanford Achievement Test Series, 10th edition) — another nationally normed assessment, widely used by homeschoolers. Requires a certified administrator to give it in some states, but not in California (since no testing is required here, there is no state rule about who can administer it for homeschool purposes). Seton and other vendors offer it under similar conditions.

Iowa Assessments (IOWA) — formerly the Iowa Test of Basic Skills. Another solid nationally normed test covering similar subject areas. Available through similar vendors.

PASS Test (Personalized Achievement Summary System) — designed specifically for homeschoolers, less widely used but offers detailed subject breakdowns.

For California families, the choice between CAT, Stanford 10, and Iowa Assessments is largely a matter of vendor preference. All three provide national percentile rankings and grade equivalents. None is considered more prestigious than the others for admissions purposes at the K–12 level.

When You Do Not Need to Test

If your child is in early elementary school, you are confident in their academic progress, and you have no near-term documentation need, there is no urgent reason to administer standardized tests. California law does not require it, and the primary value of testing is information — which you may already have from daily work.

Many experienced homeschool families test every two to three years rather than annually. This gives you meaningful trend data (is the trajectory right?) without the time and cost of annual testing for a child who is clearly on track.

If your child is approaching high school and you are thinking about UC or CSU applications, CLEP exams, dual enrollment, or scholarships, testing becomes more strategic. Building a paper trail of external academic verification in 7th and 8th grade — before the formal college prep years — gives you more options later.

The Withdrawal Step Before Any of This Matters

Before you can make any of these decisions as a PSA homeschooler, you have to actually complete the withdrawal from your child's current school and file the affidavit correctly. This is where many California families hit unexpected friction — schools that push back on withdrawal requests, administrators who misrepresent what the law requires, and families who file the PSA at the wrong time of year and create a legal gap.

The California Legal Withdrawal Blueprint at /us/california/withdrawal/ covers this first step in detail: how to submit a withdrawal letter that schools cannot legally ignore, how to time the PSA filing correctly, and what to do when a school questions your right to homeschool. Getting the withdrawal right is what makes everything else — curriculum, testing, record-keeping — go smoothly.

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