SAT/ACT Diagnostic Tests: Q&A with ArborBridge

With all of the changes to the standardized testing landscape, many families wonder about the best pathway for SAT/ACT prep. As an IEC, I've historically recommended that sophomores take a practice SAT and practice ACT in the spring to get a sense of where they stand. These diagnostic tests are full-length SAT and ACT tests that help students build a test prep plan for the upcoming summer and fall. With this in mind, I turned to our friends at ArborBridge to seek their opinion on diagnostic testing. 

I always recommend sophomores take the practice SAT and practice ACT in the spring - does this align with your philosophy? Why do you recommend that students take a diagnostic test this spring?

Yes, that absolutely aligns with our philosophy. At ArborBridge, we recommend that students take a diagnostic SAT and ACT no earlier than the spring of their sophomore year. By this point in the academic year, most students have covered enough core content—particularly in math and English—to make the diagnostic results meaningful and actionable.

Spring is also a strategic time: students have completed most of their sophomore coursework, and there's still plenty of time to build a thoughtful testing plan before junior year. Ideally, students should have completed Algebra 2, and on the verbal side, they’ve usually developed the analytical reading and writing skills needed to engage with the material on either exam.

There are exceptions, of course, for students who take advanced math courses earlier or who may be on an accelerated academic path. But for most, spring of sophomore year offers the right mix of readiness and opportunity.

How does ArborBridge interpret results? 

ArborBridge provides a comprehensive diagnostic score report that breaks down results by composite score, section or module scores, number and percentage of correct answers, and performance within each content category. Each question is also linked to our proprietary curriculum, allowing us to analyze how a student performed across both academic content areas and strategy types.

We share this detailed report alongside the broader metrics you'd expect—like section scores, composite scores, and national percentiles. When comparing SAT and ACT diagnostics, we pay close attention to percentiles to determine which test provides the stronger starting point. Additionally, we use our publicly available score improvement data to help families map out a prep timeline and set realistic goals for moving from a diagnostic score to a target score.

How much are students improving from the first diagnostic test to the real test? 

On average, ArborBridge SAT and ACT students achieved a rate of 47% to perfect in 2024. This means that generally, students who work with our expert tutors make it almost halfway to a perfect score from their starting point. Ultimately, 9 out of 10 ArborBridge SAT and ACT students score in the top 5% of test-takers. When mapping out a test prep program, we recommend using the more granular data on our site to compare each student’s starting (diagnostic) score and scoring goals. When you look at historical data that is more specific to your student’s starting point, you’re looking at data that is far more accurate and actionable in evaluating how much prep to do and how aggressively to target the student’s objectives.

How much test prep time do you typically allow before taking the real test? 

Most students can start test prep up to 4 months before their first official exam, and because nearly everyone performs better after their first attempt, we recommend planning for two or three official exams. In building a test prep timeline, we want to balance creating a long runway for improvement and avoiding burnout and fatigue with too long of a program. At minimum, most students need 6-8 weeks to start feeling confident in applying newly acquired skills and strategies.

Is it worth it for the Class of 2026 to still take both the paper ACT diagnostic and digital SAT?

For the Class of 2026, the answer depends on where the student is in their testing journey. If a student has already chosen a test, we recommend they stick with it. For those planning to take the ACT, it’s ideal to finish testing by July—before the ACT transitions formats in the fall. If a student is still deciding or expects to test into the fall, the SAT may be the safer and more consistent option, as it is already fully digital and stable.

For students in the Class of 2027 or younger, our advice is to wait—if they can—for just a little longer. ACT is expected to release a new Red Book with four sample tests on May 6, 2025, which will give us more insight into the structure and content of the new version. We’re still waiting to see if those sample tests will include scoring scales, but they will help us better support students in making an informed decision. That said, if a student wants to get started now or avoid the uncertainty, the SAT remains the more predictable choice.

Here's a deep dive on what we learned from the first administration of the new digital ACT. And more new information as of July 2025. Happy testing!