Iowa Test and Stanford Achievement Test for Ohio Homeschoolers: A Practical Comparison

Ohio no longer requires standardized testing for homeschoolers. House Bill 33 eliminated that requirement in October 2023, along with portfolio submissions and annual teacher evaluations. So if you're researching the Iowa Test or Stanford Achievement Test for your Ohio homeschool, you're not looking for mandatory compliance — you're looking for useful data.

That changes how to think about which test to choose. Without the pressure of a government mandate, the question becomes: which test actually gives you the information you need to make better curriculum decisions, prepare your child for future high-stakes exams, and build documentation that matters for college or program applications?

What the Iowa Test of Basic Skills (Iowa Assessments) Covers

The Iowa Test of Basic Skills — now published under the name Iowa Assessments — is a nationally normed achievement test developed by the University of Iowa and currently published by Riverside Insights. It measures skills in reading, language arts, mathematics, science, and social studies across grades K–12. The test has been used in both public schools and homeschool settings for decades and generates grade equivalent scores, percentile ranks, and standard scores.

For Ohio homeschoolers, the Iowa Assessments cover most of Ohio's six required subject areas — English language arts, math, science, and social studies — though history and government are not assessed as standalone subjects in most grade-level editions. The test is well-suited to identifying where a student stands relative to national norms and where gaps exist in foundational skills.

Format: Multiple-choice and written components depending on grade level. Most sections are timed. Total testing time ranges from roughly three to five hours spread across multiple sittings for upper grades.

Reading level: The test uses straightforward language and is considered accessible even for students who don't have strong test-taking experience, though the timed format can challenge students who work methodically rather than quickly.

Score output: The primary outputs are national percentile ranks (how your child compares to a national sample), grade equivalent scores (the grade and month at which the average child scored the same), and standard scores. The national percentile rank is the most useful number for most purposes.

What the Stanford Achievement Test (SAT-10) Covers

The Stanford Achievement Test, Tenth Edition (SAT-10) is published by Pearson and covers similar content areas: reading, mathematics, language, spelling, science, listening, and environment/social studies depending on grade level. It has historically been one of the most widely used standardized tests in homeschool settings because it has a strong track record of use outside traditional classroom environments and is available through multiple homeschool testing providers.

The Stanford 10 generates national percentile ranks comparable to those produced by the Iowa Assessments. Results from the two tests are not interchangeable — a 70th percentile score on one does not necessarily equal a 70th percentile score on the other — but both use current national norms derived from large samples of U.S. students.

Format: Multiple-choice throughout most grade levels. Largely untimed for the Primary and Intermediate levels used with younger students, which makes it notably less stressful for children who struggle with timed assessments. Upper-level editions (grades 6 and up) are more timed.

Reading level: The SAT-10 Primary levels are considered easier to administer at home due to the untimed format and clear instructions that the administering parent can read aloud to the student.

Score output: National percentile ranks, stanine scores (a 1–9 scale), and grade equivalent scores. The report also includes a Total Reading and Total Mathematics composite that gives a quick overview without requiring deep score interpretation.

Iowa Test vs. Stanford Achievement Test: Key Differences for Ohio Families

Both tests are nationally normed, widely accepted, and generate useful percentile rankings. The practical differences come down to administration format, subject coverage, and what you need the results for.

Timed vs. untimed testing: The Iowa Assessments are timed throughout. The Stanford 10 includes untimed levels for primary grades, which matters considerably if your child has test anxiety, a processing speed difference, or has had negative experiences with timed academic evaluation. If time pressure causes your child to shut down rather than demonstrate their actual knowledge, the Stanford 10's untimed lower levels give you cleaner data about what they actually know.

Science and social studies coverage: Both tests assess science and social studies, but the Iowa Assessments are generally considered stronger in these areas at middle and upper grade levels, with more comprehensive science coverage. If your reason for testing is partly to verify that your science curriculum is producing genuine knowledge gains, the Iowa Assessments may give you more actionable feedback.

Availability for home administration: Both tests can be administered at home by the parent in some editions, without requiring a certified proctor. This varies by test edition and grade level. The California Achievement Test (CAT) is another option explicitly marketed for home administration at all grade levels, which is worth noting if home administration without a proctor is important for your family's schedule.

Recognition by testing centers and co-ops: Many Ohio homeschool co-ops and testing centers offer proctored Iowa Assessments sessions because of the test's long history in educational settings. Finding a proctored session for the Iowa Assessments is typically easier in Ohio's metropolitan areas (Columbus, Cleveland, Cincinnati) than finding a comparable session for the Stanford 10, which is more commonly ordered through mail-in homeschool testing services.

How to Order Each Test in Ohio

Iowa Assessments: Riverside Insights sells directly to homeschool families through several authorized distributors. Homeschool co-ops frequently organize group testing sessions, which reduces cost and provides a natural proctoring environment. The test can also be ordered through services like BJU Press Testing or Seton Testing Services, which mail materials and provide scoring.

Stanford Achievement Test: Available through Seton Testing Services, CHC Testing (formerly Christian Home Educators), and similar homeschool testing services. Most of these services mail the test, you administer it at home according to the instructions provided, then mail it back for scoring. Results typically return within two to four weeks.

California Achievement Test: The CAT is available from Seton Testing Services and can be fully administered and scored at home without mailing anything. It uses an older norm reference than the Iowa or Stanford 10, which affects the accuracy of national percentile comparisons, but it remains a widely used option for families who need maximum scheduling flexibility.

Pricing: Expect to pay roughly $25–$60 per student for mail-in scoring services, depending on the test and grade level. Proctored group sessions through co-ops are often comparable in cost and have the benefit of a structured testing environment.

What the Scores Actually Mean — and What They Don't

A national percentile rank of 65 means your child performed as well as or better than 65 percent of the national norming sample. It does not mean your child is at grade level, above grade level, or behind. "Grade level" is conventionally placed at the 50th percentile, but national norms vary by test publisher and norming year.

A score below the 50th percentile in a specific subtest tells you that area is worth examining more closely. It does not tell you why — whether the curriculum covers that content area in a later year, whether the test format disadvantages your child's learning style, or whether there's a genuine gap to address. Interpreting scores well means looking at subtest patterns across multiple years, not reacting to a single year's numbers in isolation.

For Ohio homeschoolers using standardized test results as part of a high school academic record, raw percentile scores serve as supporting documentation — not the primary record. The high school transcript listing courses, credits, and a calculated GPA is what Ohio universities require. A solid ACT or SAT score provides the strongest external validation of that transcript.

Building the Record Alongside the Test

Standardized test results are one type of documentation. They don't document specific coursework, credit hours, or the depth of a student's study in Ohio's six required subjects. For that, you need a portfolio or course record running alongside the test data.

This is particularly true for subjects the Iowa Assessments and Stanford 10 assess less thoroughly — history, government, and arts — and for any year where your curriculum diverges significantly from the standard scope and sequence a test assumes.

The Ohio Portfolio & Assessment Templates includes frameworks for tracking all six required subjects alongside your test results, so that when it comes time to build a high school transcript or document a middle school year, you have both the objective score and the detailed course record to back it up.

Ohio Revised Code §3321.042 governs home education exemptions. Standardized testing is voluntary for Ohio homeschoolers as of October 3, 2023 (HB 33 implementation date). Test availability, pricing, and publisher information are subject to change — verify current options directly with test providers.

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