ERB vs. ISEE: Breaking Down the Differences

If you are navigating the independent school world, you have likely heard two acronyms thrown around a lot: ERBs and ISEE.

Because both tests are developed by the exact same company (the Educational Records Bureau), they share a massive amount of DNA. They cover similar subjects, look alike structurally, and even use the same unique scoring metrics.

However, they serve very different purposes in your child’s academic journey. Knowing both the differences and the overlap, can save your family a lot of testing fatigue. Let’s break down exactly how they compare.

Purpose: Assessment vs Admissions

The absolute biggest difference between these two exams isn’t what’s on them, but who sees the scores and why.

• The ERBs (CTP-5): This is an “in-school” assessment tool. Schools use it annually to track student progress, evaluate curriculum, and see how their classes stack up against national and independent school averages. Generally, ERB scores are not used for admissions.
  • The Major Exception: How Important Are 5th Grade ERBs for Middle School Admissions? If your student is applying to a new middle school, admissions committees will occasionally look at their 5th-grade ERB scores as part of the application packet.
• The ISEE (Independent School Entrance Exam): It’s right there in the name. This is purely an entrance exam designed specifically for admissions. The Middle Level is used for middle school entry, and the Upper Level is for high school admittance. Unlike the ERB, you get to see these results before deciding where to send them.

Format & Layout

While the subject matter overlaps, the testing experience feels very different for a student.

Pro Tip on ISEE Registration: Because you can only test once per season, planning ahead is critical. Check out our comprehensive Guide to ISEE Registration and Testing Options to map out your strategy.

Content & Difficulty

ERB CTP-5 Subtests: Vocabulary, Verbal Reasoning, Reading Comprehension, Writing Mechanics, Writing Concepts and Skills, Quantitative Reasoning, Math 1, Math 2, (sometime Science) 

Middle Level ISEE Sections: Verbal Reasoning, Quantitative Reasoning, Reading Comprehension, Mathematics Achievement, and the Essay

Because the same parent company designs both tests, both overlap on four core pillars: Mathematics, Quantitative Reasoning, Verbal Reasoning, and Reading Comprehension.

However, the ISEE takes the gloves off. Generally speaking, the ISEE takes the foundational ERB material, and ups the difficulty level by at least a full grade. It features less variety in question types, making it easier to “nail down” and practice for, but it requires significantly deeper mastery and faster pacing.

Stanine Scoring 

When you receive a score report for either the ERB or the ISEE, you won’t see a standard “90%” or “A-.” Instead, you’ll see Stanines.

• Stanine is short for “standard nine.” It is a scoring system that scales student performance from a low of 1 to a high of 9 based on a bell curve.
• A score of 5 is the exact national average.
• Scores of 7, 8, and 9 represent the top tiers of test-takers.

Read our post “What is a Stanine? Reading Score Reports for ERB and ISEE,” where we break down how to interpret these rankings against both National Averages and Independent School Averages.

Prepping for Both

Here is the great news for parents: Prep for the ERB flows seamlessly into the ISEE, and vice versa. Because the core skills—stamina, multiple-choice strategies, and advanced grade-level math/verbal concepts—are identical, preparing for one inherently prepares your student for the other.

At Mulholland Prep, we’ve built proprietary, stress-free prep programs designed to boost both scores and classroom confidence:

• Doodle-Filled Workbooks: We make prep engaging. We feature two specialized workbooks packed with custom doodles—one for the Middle Level ISEE and one for the ERB CTP-5.
• Curriculum Boost: The concepts we teach often give students a sneak peek at what they’ll learn in school the following year, skyrocketing their daily academic confidence.
• One-on-One Expertise: Your student will team up with a test-prep expert to target their specific pacing and conceptual blind spots.
  Mulholland Prep

Take a Free ISEE Diagnostic on PEAK!

We have full-length, highly accurate practice tests available online through our proprietary PEAK platform, which perfectly mimics the official digital ISEE experience.

Mulholland Prep

• New to us? Click here to take a free diagnostic test and get a detailed stanine breakdown.
• Already prepping with us? We’ve got you covered. Shoot us a quick email at peak@mulhollandprep.com and we’ll make sure all five practice tests are added to your student’s plan for no extra cost!

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