We don't guess about what works. Every feature of ISP is grounded in decades of peer-reviewed research from cognitive psychology and learning science.
The 2 Sigma Problem: Benjamin Bloom (1984) found that students receiving 1:1 tutoring with mastery-based learning perform 2 standard deviations better than traditional classroom instruction.
An average student becoming a top 2% student. ISP is built to deliver this at scale.
Your brain's limited workspace
Working memory can only hold about 4 items at once. When instruction overloads this, learning stops. Traditional school's 6-hour days exhaust cognitive resources by hour 3.
Don't move on until you've got it
Benjamin Bloom found that 1:1 tutoring with mastery-based learning moves average students to the 98th percentile—a 2 standard deviation improvement.
Testing IS learning
Testing isn't just measurement—it's one of the most powerful learning tools. Students who practice retrieval remember 67% after a week vs 40% for re-reading.
Spread it out, remember forever
Cramming works for tomorrow. Spacing works for life. Studies show 2-3x better long-term retention when learning is distributed over time.
Show before asking to do
For novices, watching step-by-step solutions is more effective than problem-solving. It reduces cognitive load and provides mental models to follow.
Mix it up to learn it deeper
Blocked practice (one type at a time) feels effective but fails. Interleaved practice doubled test scores in one study: 77% vs 38%.
Focused effort on weaknesses
Practice doesn't make perfect—practice makes permanent. Deliberate practice targets specific weaknesses with immediate feedback and clear goals.
Hard now = easy later
Learning that feels easy often doesn't last. Strategies that slow initial learning—like spacing and interleaving—produce stronger long-term retention.
Fast basics free up brainpower
When foundational skills become automatic, working memory is freed for higher-order thinking. Students who struggle with basic facts can't focus on complex problems.
Words + pictures, done right
Dual coding—words and visuals together—enhances learning. But redundancy (reading slides while hearing the same words) hurts it.
Explicit beats discovery for novices
For beginners, clear explanations outperform open-ended exploration. Direct instruction has one of the largest effect sizes in education research.
Immediate, specific, actionable
A letter grade tells you where you stand, not how to improve. Effective feedback answers: Where am I going? How am I doing? What's next?
Depth of thinking, not just difficulty
DOK measures cognitive complexity, not just hardness. Level 4 (extended thinking) requires applying knowledge to new situations—like teaching others.
We didn't invent these principles. These scientists did—through decades of rigorous research.
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