Your child is in 5th grade but struggling with 3rd grade concepts

The ExcelOS Diagnostic is an adaptive assessment that figures out exactly what a student knows — and more importantly, where the gaps in their foundation are, even if those gaps are from earlier grades. Instead of just telling you "you're at a Grade 5 level in math," it pinpoints the specific lessons from previous grades that are holding you back, then builds a personalized plan to fill them in the most efficient order.

The Quick Check takes 5–8 minutes (8–15 questions). The Full Diagnostic takes 20–35 minutes (30–50 questions). Stronger students tend to finish faster because the system can confirm mastery more quickly. The test doesn't have a fixed number of questions — it stops when it's confident enough in its assessment.

The Quick Check gives you a high-level snapshot — which subject areas are on track and which need attention. Think of it like a check-up. The Full Diagnostic goes deeper — it identifies the exact earlier-grade skills causing the gaps and creates a customized lesson plan to address them. Think of it like a full examination with a treatment plan. We recommend taking the Full Diagnostic at the start of a semester and using Quick Checks monthly to track progress.

Yes. Each time you take a diagnostic, it uses different questions, so your results reflect your current knowledge — not memorized answers. After completing your lesson plan, we recommend a follow-up Quick Check to confirm that the gaps have been closed.

After every response, the system uses advanced statistical models to estimate the student's ability level, then selects the question that will reduce its uncertainty the most. If the student answers correctly, the next question gets harder. If they answer incorrectly, it gets easier. The system also factors in how long the student takes to respond — more on that below.

Yes, but you're never penalized for being slow. The system looks at four distinct patterns:

• Correct and fast — strong mastery. The student clearly knows this skill.
• Correct but slow — the student understands the concept but isn't fluent yet. The plan will include reinforcement practice, not re-teaching.
• Incorrect and slow — the student tried but genuinely doesn't know the material. Strong signal of a gap.
• Incorrect and fast — likely a guess. The system gives this response less weight so it doesn't skew the results.

This means our diagnostic distinguishes between a student who understands a concept but needs more practice and a student who hasn't learned it at all — and creates a different plan for each.

No. Students are never penalized for guessing. However, the system is designed to detect likely guesses — if a student answers correctly but unrealistically fast, that response carries less weight in the overall assessment. This protects accuracy without discouraging students from trying.

The system is designed to achieve 90% or higher classification accuracy — meaning if we tested the same student twice with different questions, we'd reach the same conclusion 9 times out of 10. Every question in our item bank has calibrated statistical parameters that are continuously refined as more students use the platform. Questions that underperform are automatically flagged and retired, keeping the diagnostic sharp.

ExcelOS maintains a Skill Connection Map — a network of over 7,200 lessons linked by prerequisite relationships. When a student answers a question incorrectly, the system doesn't just mark it as "wrong." It looks up what earlier skills that question depends on, then tests those prerequisites. If the student fails the prerequisite too, it goes deeper. If they pass it, we've found the exact boundary where understanding breaks down. This is what allows us to say "you're strong through Grade 5, but you're missing two specific Grade 6 skills" instead of just "you're below grade level."

The Full Diagnostic can detect gaps up to four grade levels below the student's enrolled grade. For the lesson plan, we focus remediation within two grade levels. Research shows that going further back is rarely necessary and can feel discouraging — the highest-impact improvements are almost always found within that two-grade window.

Some skills act as a gateway to many others. For example, understanding equivalent fractions in Grade 4 is a prerequisite for ratios, proportional reasoning, percent calculations, and more. Our system identifies these high-impact skills automatically. If a gateway skill is flagged as a gap, it gets the highest priority in the lesson plan because fixing it unlocks progress across multiple topics at once.

Not all gaps are equal. A skill that is a prerequisite for eight other skills is more valuable to fix than one that only blocks one. The system calculates the impact score of each gap — how many downstream skills will become accessible once it's filled — and prioritizes the highest-impact gaps first. This ensures students see the fastest possible improvement in their grade-level work.

Each unit in the plan includes a tutorial lesson from the ExcelOS library (with learning objectives, explanations, and worked examples), practice questions to reinforce the concept, and a checkpoint test to verify mastery before moving on. Importantly, the checkpoint uses different questions than the diagnostic — so we're confirming the student actually learned the concept, not just memorized an answer.

Teachers can assign the Quick Check or Full Diagnostic to an entire class in one step. They set a due date and optional instructions, then track completion in real time. As students finish, results appear on the class dashboard — including individual student profiles, a domain-by-domain heat map, and the students who need the most support listed first.

This is the feature teachers tell us they find most valuable. The system identifies skill gaps that multiple students in the class share. For example, if 60% of a Grade 7 class is weak on Grade 4 equivalent fractions, that's not 18 individual problems — it's one group re-teaching opportunity. The report bundles shared gaps into suggested group lesson plans with estimated class periods needed, so teachers can address the biggest bottleneck for the whole class before moving to individual remediation.

Yes. School administrators get a dashboard that shows performance summaries across all grades and subjects, comparisons between classes in the same grade, and school-wide shared gaps. This supports data-driven decisions about curriculum priorities, resource allocation, and intervention planning. Teachers can only see data for students in their own classes, while administrators see the full picture.

We recommend running a Full Diagnostic at the start of a semester as a baseline, then monthly Quick Checks to track progress. Teachers see trend lines for each student and the class as a whole — so improvement is visible and measurable. After students complete their lesson plans, a follow-up Quick Check confirms whether the gaps have truly closed. All of this data is preserved across semesters, giving a longitudinal view of each student's growth.

Reach out to us at info@excelos.co or use the Request a Demo form on our homepage. We offer flexible volume-based pricing for schools, pilot programs so you can test it with a few classes before committing school-wide, and our team handles setup so you can be up and running in days.

Because real learning — like fitness or any meaningful skill development — requires consistent, deliberate effort over time. One month simply isn't long enough to identify gaps, work through a personalized lesson plan, and see measurable results. The shortest time frame in which we believe students can expect meaningful improvement is four months — roughly one academic semester (September to December, January to April, or May to August). That's why our plans are billed on a quarterly or annual basis.

That said, we want you to try ExcelOS with complete confidence. If it's not the right fit, you can cancel within the first 30 days for a full refund, no questions asked.

We offer three plans for individuals and families:

• Single Subject — $12.49/month (billed quarterly at $49.99). One subject, one student.
• Semester Pass — $19.75/month (billed quarterly at $79). All four subjects, one student.
• Family Annual — $199/year. All subjects for up to three children, with a parent dashboard.

For schools, we offer custom volume-based pricing. Contact us for details.

You can cancel anytime directly from the Settings tab in your student or parent account — no phone calls, no hoops to jump through. If you cancel within the first 30 days, you'll receive a full refund. If you need any help, feel free to email us at info@excelos.co.

We offer something better than a free trial — a 30-day money-back guarantee. Sign up, take the diagnostic, start your lesson plan, and see the platform in action. If it's not the right fit within the first 30 days, we'll refund you in full, no questions asked. This way you get to experience the real product, not a stripped-down trial version.

The Semester Pass and Family Annual plans include all four subjects (Math, English Language Arts, Spanish, and Computer Science). The Single Subject plan lets you choose one subject if that's all you need. You can upgrade from a single subject to the full Semester Pass at any time — we'll prorate the difference.

ExcelOS content is aligned to the Common Core State Standards (CCSS) for Mathematics and English Language Arts. Our Spanish curriculum follows the ACTFL World-Readiness Standards for Learning Languages and the ACTFL Proficiency Guidelines, progressing from Novice through Advanced levels. Our Computer Science curriculum is aligned to the CSTA K–12 Computer Science Standards. All four subjects cover Kindergarten through Grade 12, with over 7,200 individual lessons and 25,000 learning objectives across the platform.

Yes. While our primary alignment is to the Common Core standards, the mathematical and English Language Arts skills we cover overlap significantly with Canadian provincial curricula. The core concepts and progressions are largely the same across frameworks — what varies is mainly the grade placement of certain topics, which our adaptive diagnostic handles naturally by testing the student where they actually are, not where a specific curriculum says they should be.

ExcelOS covers Kindergarten through Grade 12 across all four subjects. Mathematics runs from counting and number recognition all the way through calculus and limits. English Language Arts starts with letter recognition and phonics and goes through advanced writing, rhetoric, and literary analysis. Spanish covers Novice through Advanced proficiency. Computer Science progresses from unplugged activities and block-based coding to advanced data structures, algorithms, and machine learning.

Absolutely. Diagnostic results are only visible to the student, their parents (if on a family plan), and their teachers (if enrolled through a school). Individual student data is never shared with other students, sold to third parties, or used for advertising. In school settings, teachers only see data for students in their own classes, and administrators see aggregate data for their school.

Yes. Every student response helps the system refine its understanding of each question's difficulty and effectiveness. Questions that don't perform well statistically are automatically flagged for review and eventually retired. The more students use ExcelOS, the sharper the diagnostic becomes.

Yes. ExcelOS works on any device with a modern web browser — desktop, laptop, tablet, or phone. For the diagnostic test specifically, we recommend a tablet or larger screen for the best experience, since some questions involve reading passages or code snippets that are easier to read on a larger display.

Because the diagnostic is adaptive and self-paced, it naturally accommodates different learning speeds — there are no time limits that penalize slower test-takers. The system's response-time analysis distinguishes between a student who is slow because they're struggling and a student who is slow because they process information differently but ultimately understands the material. If your child has specific accommodations, please reach out to us at info@excelos.co and we'll work with you to ensure the best experience.

We'd love to hear from you. Please reach out to us at info@excelos.co or use the Contact Us button on our homepage. We typically respond within 24 hours.