A Growth Score measures how much a student learns over time, rather than just their current achievement. It's useful for tracking individual progress, especially in homeschooling.
Research from the National Home Education Research Institute (NHERI) shows that homeschooled students typically score 15 to 25 percentile points higher than public school students on standardized academic achievement tests. According to the National Center for Education Statistics (NCES), approximately 3.3 million students were homeschooled in the United States as of 2023, representing roughly 6% of the school-age population.
What is a growth score?
A Growth Score tracks how students learn over time, not just their scores at one moment. The most common type is the Student Growth Percentile (SGP). This compares a student's growth to others with similar past test scores. Scores range from 1 to 99. For example, an SGP of 85 means a student grew more than 85% of peers starting at the same level. This focus on growth is especially useful for homeschoolers, where personal progress matters more than fitting arbitrary grade levels.
How growth scores differ from other metrics
Growth Score vs. Percentile Rank: Percentile rank measures how a student is doing compared to all other students in the same grade. Growth scores, on the other hand, compare improvement among peers with similar past scores. Two students can have the same growth score but different achievement levels.
Growth Score vs. Grade Equivalent: Grade equivalents show what grade a typical student would score. Growth scores, however, track progress consistently over years without the confusion of grade equivalents. Remember: high achievement doesn’t always mean high growth.
Nwea MAP growth: The most common system
The NWEA MAP Growth uses the RIT scale, which ranges from about 100 to 350. This scale is great because it works for all grades, from kindergarten to 12th grade. It measures progress with equal intervals, so the score differences are consistent across levels. The test adapts difficulty based on answers, aiming to find a level where students get around half right. There are two types of norms: performance norms (compared to grade-level peers) and growth norms (compared to those with similar starting points).
Value for homeschoolers
Growth scores fit perfectly with homeschooling’s focus on individual progress. A student might score below grade level but still show great growth. This helps validate your teaching methods. Tracking growth over time helps pinpoint when lessons are effective and when they need tweaking. Many states require proof of adequate educational growth, and Growth Scores provide solid evidence beyond single-point scores. Using the same assessment each year gives you a clear view of learning trends. It shifts the focus from keeping up with others to asking, 'Am I making progress?'
The bottom line
Growth scores are what homeschool parents really want to know: is my child learning? Unlike achievement scores that compare to grade-level standards, growth scores show personal improvement over time. One growth score alone doesn’t tell the whole story, but tracking growth over multiple tests reveals patterns that can guide your teaching. Consider using BetterSchool's assessment tools year after year to gather meaningful growth data. Focus on progress, not just where your child stands.
