The GreatSchools.org Dilemma: What That 1-10 Rating Really Means for Boston Homebuyers

🔍The Number Everyone Sees, Nobody Understands

If you're shopping for homes in Greater Boston, you've seen it: that single 1-10 number next to every school on Zillow, Redfin, and Realtor.com. It's usually the first thing buyers check. Towns with 9+ ratings command significant premiums. Homes near 7-rated schools sit longer on the market.

But here's what most buyers don't know: that single number is actually a weighted average of up to three completely different metrics, each measuring something different, and the formula changes every few years based on criticism and parent feedback.

Welcome to GreatSchools.org—a nonprofit founded in 1998 that has become the de facto arbiter of school quality in American real estate. Their 1-10 rating isn't just influential; it's ubiquitous, appearing on listings for over 138,000 schools and reaching 150 million monthly visitors through real estate platforms.

⚙️How the Rating Actually Works (It's Complicated)

GreatSchools.org calculates that 1-10 number by combining up to three "themed ratings":

Here's where it gets interesting: GreatSchools itself admits these metrics aren't equally valid. Their internal "strength score" system gives Student Progress the highest weight (5/5) because research shows it's the least correlated with students' socioeconomic backgrounds. Test Scores get a lower strength score (3/5) because they're heavily influenced by family income.

📉What Changed (and Why It Matters)

GreatSchools.org's methodology isn't static—it's reactive. The rating system has undergone multiple contradictory revisions:

The 2020 "Pro-Equity" Era: After journalistic investigations showed the ratings effectively penalized schools serving low-income and minority students, GreatSchools overhauled the system. They increased the weight of "Student Progress" (growth) and added an "Equity Rating" that measured how well schools served disadvantaged groups.

The 2025 Reversal: Just five years later, GreatSchools removed the Equity Rating from the 1-10 calculation entirely, citing "a desire for a simpler experience" for parents. Now, equity is just a binary badge—a "special message" if a school would have scored 5+ on the old equity metric. It's no longer factored into the number that appears on Zillow.

The platform is caught in a permanent tug-of-war between academic validity (which demands complexity) and market-driven simplicity (which demands a single, clean number). As of 2025, simplicity has won.

🔬What the Research Actually Says

Multiple independent researchers have analyzed GreatSchools ratings, and their findings are consistent and damning:

Test Scores ≠ School Quality: Education policy experts note that factors schools can control typically explain only about 20% of test score variation. At least 60% of test scores are determined by students' socioeconomic status—family income, parental education, neighborhood resources. Low-income students tend to score lower and high-income students tend to score higher, regardless of teaching quality.

Economist Research (2022): A rigorous study by economists including Nobel laureate Josh Angrist compared GreatSchools rating components to actual "value-added" measures of school performance. The findings were split:

In other words: the part of the rating GreatSchools now allows as the sole basis for a 1-10 score (Test Scores) is the part researchers proved is invalid. The valid metric (Student Progress) isn't available in all states.

💰The Real Estate Impact: Why This Number Costs You Money

GreatSchools.org isn't just an information platform—it's a business. As a nonprofit, it licenses its data to Zillow, Redfin, Realtor.com, and other major real estate platforms. This integration makes the 1-10 rating a primary filter for home searches and a price signal embedded directly into listing pages.

The market impact is measurable:

🏘️The Feedback Loop: How Ratings Reinforce Inequality

Here's where it gets systemic. Because Massachusetts public schools are funded largely by local property taxes, GreatSchools ratings create a self-reinforcing cycle:

Meanwhile, schools in lower-income areas face the opposite spiral: low ratings (from low test scores reflecting poverty, not poor teaching) → depressed home values → less tax funding → fewer resources → lower scores → lower ratings.

🎯Greater Boston Reality Check: Where This Plays Out Locally

Let's make this concrete with Greater Boston examples:

The Lexington Premium: Lexington consistently receives 9-10 GreatSchools ratings and a median home price around $1.49M. Nearby Reading has similarly strong schools (8.7 rating on our scale, 9+ on GreatSchools) but costs around $892K median. The $598K difference? Partially justified by Lexington's STEM focus and college outcomes—but also significantly driven by prestige and the power of that "10" rating.

The Winchester Question: Winchester (9.2 rating, $1.26M median) vs. Melrose (8.8 rating, $937K median). Both are excellent school districts. Both send kids to top colleges. The $323K gap is partially about Winchester's proximity and character—but that 9.2 vs 8.8 rating difference on real estate listings drives perception and demand.

The Value Play: Franklin has an 8.1 rating and costs around $725K median—making it one of the best value propositions for families who want 8+ schools without the Lexington/Winchester premium. But many buyers filter it out of their search because they're targeting "9+ schools only" on Zillow.

✅What Smart Buyers Should Do Instead

Don't ignore GreatSchools ratings entirely—they're useful as a starting point filter. But don't let a single number drive a $300K+ decision. Here's the smarter approach:

1️⃣Step 1: Prioritize the "Student Progress" Component

When you look up a school on GreatSchools.org, don't just look at the summary 1-10 score. Scroll down and find the "Student Progress" or "Academic Progress" sub-rating. This is the metric researchers validated as less biased and more predictive of actual school effectiveness.

A school with a 7.5 summary rating but a 9.0 Student Progress rating is likely outperforming a school with an 8.5 summary rating and a 6.0 Student Progress rating—even though the numbers appear reversed.

2️⃣Step 2: Look for the New "Academic Success Indicator"

Schools that would have scored 5+ on the old Equity Rating now display a badge or message indicating "strong academic outcomes for all students." This tells you the school isn't just serving affluent families well—it's helping all demographic groups succeed. That's a green flag.

3️⃣Step 3: Dig Into Disaggregated Data

GreatSchools still publishes performance data broken down by student subgroups (race, income, special education status). Look at these numbers. A school with a 9.0 overall but massive gaps between white and minority student outcomes is a warning sign. A school with an 8.0 overall but consistently strong outcomes across all groups is often the better choice.

4️⃣Step 4: Cross-Reference with MA DESE Official Data

Don't rely on a single rating source. Go directly to the Massachusetts Department of Elementary & Secondary Education profiles and look at:

5️⃣Step 5: Visit Schools and Talk to Parents

No algorithm captures school culture, teacher engagement, or how well the administration handles issues. The best data on these factors comes from:

6️⃣Step 6: Balance Schools Against Other Priorities

School quality is hugely important—for your kids AND for resale value. But it's not 100% of the decision. A 9.5-rated district with a brutal commute and 1% appreciation will lose to an 8.5-rated district with a manageable commute and 4% appreciation over a 10-year ownership horizon.

Use our Town Comparison Tool to see how school ratings stack up against price, commute, investment potential, and lifestyle fit. We calculate a holistic Investment Score where schools are 25% of the equation—important, but not everything.

🎯Our Take: How We Handle School Ratings Differently

At Boston Property Navigator, we've built our school rating methodology specifically for Greater Boston, using MA DESE accountability ratings, MCAS performance data, college matriculation rates, and student-teacher ratios. We update annually when new MCAS data is released and normalize scores using z-score standardization to account for demographic differences.

More importantly, we don't reduce everything to a single number. Our town profiles show:

You can customize how much weight each factor gets and see instant rankings that reflect YOUR priorities—not a one-size-fits-all algorithm designed to serve 138,000 schools nationwide.

🔑Key Takeaways

📚Continue Your Research

Want to go deeper on school ratings and Greater Boston home buying strategy?

📖Sources & Methodology

This analysis is based on:

Disclaimer: This post is for educational purposes and represents our interpretation of publicly available information about GreatSchools.org's methodology and its market impact. We are not affiliated with GreatSchools.org. School ratings, methodologies, and home prices change over time. Always verify current data before making real estate decisions. This is not real estate, legal, or investment advice.

Publication Date: November 20, 2025