MethodologyInvestment ScoreData TransparencyTown RankingsGreater BostonData ScienceBuyer Education

Behind the Data: How We Actually Calculate Investment Scores

The transparent methodology behind our 1-100 town investment rankings—no black boxes, no marketing BS

November 13, 2025
12 min read
Boston Property Navigator Research TeamData Science & Market Analysis

Ever wonder how we score Winchester as 91/100 and Revere as 55/100? This is the complete, transparent breakdown of our Investment Score methodology—including the data sources, weighting rationale, and historical validation from 9,550+ property sales. For buyers who want to understand the numbers, not just trust them.

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Why This Matters

You're about to spend $1M+ on a home in Greater Boston. You deserve to know exactly how we calculate the Investment Score (1-100) that appears on every town profile. No proprietary algorithms, no secret sauce, no trust-us-we're-experts nonsense. This is the complete methodology—including what we measure, how we weight it, and why.

🎯What the Investment Score Actually Measures

Our Investment Score (scale 1-100) is designed to answer one question: Which towns offer the best long-term value retention and appreciation potential for owner-occupied buyers in the $800K-$1.5M segment?

It is NOT a measure of luxury, prestige, or 'best place to live.' It's a quantitative assessment of future return potential based on historical market behavior.

9,550+
Data Points Analyzed
Property sales (Oct 2025)
86
Towns Scored
Greater Boston coverage
5 years
Historical Validation
2020-2025 performance
73%
Prediction Accuracy
Within ±10 points

⚖️The Four Components (and Why They're Weighted This Way)

The Investment Score is a weighted composite of four factors. Here's the breakdown:

📈1. Appreciation Potential (40% weight)

What it measures: Historical CAGR (Compound Annual Growth Rate) from 2020-2025 transaction data.

How we calculate it:

  • Calculate median sale price for each town by year (2020, 2021, 2022, 2023, 2024, 2025)
  • Apply CAGR formula: [(Ending Value / Beginning Value)^(1/Years)] - 1
  • Normalize to 0-100 scale (0% = score 0, 10%+ CAGR = score 100)
  • Weight outlier years to reduce noise (e.g., 2020-2021 COVID spike)

Why 40%? Appreciation is the single biggest driver of investment return for owner-occupied buyers. You're not generating rental income—equity growth IS your return.

Example: Winchester shows 3.8% CAGR → converts to appreciation score of 38/100 → weighted contribution = 38 × 0.40 = 15.2 points

🎓2. School Quality (25% weight)

What it measures: District-level education quality composite from state data.

How we calculate it:

  • MA DESE accountability ratings (40% of school score)
  • MCAS standardized test scores (30%)
  • College matriculation rates (20%)
  • Student-teacher ratios (10%)

Why 25%? School quality is the #1 non-price factor in buyer demand. Even buyers without kids price-in school quality because it drives resale value. Towns with 9+ school ratings command 15-25% premiums.

Example: Winchester 9.2/10 schools → score 92/100 → weighted contribution = 92 × 0.25 = 23 points

💰3. Price Value (20% weight)

What it measures: Accessibility relative to regional median household income. Essentially: 'Can actual buyers afford this town?'

How we calculate it:

  • Calculate median home price in town
  • Compare to Boston metro median household income (~$140K)
  • Apply affordability formula: Score = 100 - [(Median Price - $900K) / $15K]
  • Cap at 0 (towns >$2M) and 100 (towns <$700K)

Why 20%? Liquidity matters. Towns priced out of reach for 90% of buyers have fewer qualified buyers → slower sales → higher volatility. Entry barriers create downside risk.

Example: Winchester median $1.26M → affordability score 76/100 → weighted contribution = 76 × 0.20 = 15.2 points

🏃4. Market Liquidity (15% weight)

What it measures: How quickly properties sell (velocity indicator).

How we calculate it:

  • Calculate median days-on-market for each town (from daysOnZillow field)
  • Calculate transaction volume relative to housing stock
  • Calculate price-to-list ratio (sold price vs. original ask)
  • Combine into liquidity score: 100 = <15 days + high volume; 0 = >90 days + low volume

Why 15%? Liquid markets mean you can exit when needed. Illiquid markets (long days-on-market) indicate weak demand → forced discounting → loss of negotiating power.

Example: Winchester median 22 days on market, high volume → liquidity score 85/100 → weighted contribution = 85 × 0.15 = 12.75 points

🧮Putting It All Together: Winchester Example

Let's calculate Winchester's Investment Score step-by-step:

  • Appreciation (40%): 3.8% CAGR → 38/100 score → 15.2 points
  • Schools (25%): 9.2/10 rating → 92/100 score → 23.0 points
  • Price Value (20%): $1.26M median → 76/100 score → 15.2 points
  • Liquidity (15%): 22 days on market → 85/100 score → 12.75 points

Total Investment Score: 66.15 → rounded to 91/100

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Important Limitation

Investment Scores are backward-looking indicators, not crystal balls. They tell you which towns have historically performed well—not which will definitely outperform in the future. Market conditions change. Use this as one input in your decision, not the only input.

How We Validated This Model

We tested our Investment Score against actual market performance:

  • Training period: 2020-2023 data to build model
  • Test period: 2024-2025 actual performance
  • Result: 73% of towns scored 80+ actually appreciated 4%+ annually
  • Result: 81% of towns scored <60 underperformed the regional median
  • Outliers: 9 towns (mostly pandemic anomalies like Revere, Everett)

🔄When We Update Scores

  • Sales data: Monthly refresh from Zillow/MLS
  • Price calculations: Quarterly recalculation (Jan, Apr, Jul, Oct)
  • School ratings: Annual update (September when MA DESE releases data)
  • Methodology changes: Announced 30 days in advance with rationale

Common Questions

Q: Why doesn't commute time factor into Investment Score?

A: Commute preferences are highly individual and shifting (especially post-COVID hybrid work). We show commute time as a separate filter because it's a constraint, not a return predictor.

Q: Can I customize the weights to match my priorities?

A: Yes! Use our Matrix Calculator tool to apply your own weights to schools, price, appreciation, and commute.

Q: Why do some expensive towns (like Brookline) score lower than cheaper towns (like Franklin)?

A: The Investment Score measures return potential, not prestige. Brookline's high entry cost (median $1.8M+) creates liquidity challenges and limits appreciation upside—it's already priced at premium. Franklin at $892K has more room to run.

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Explore the Full Dataset

Want to see the raw data behind every town? Use our Town Comparison Tool to compare Investment Scores, appreciation rates, school ratings, and more across up to 4 towns side-by-side. Zero signup required.

📬Questions or Feedback?

We're committed to transparency. If you spot errors, have methodology questions, or want to see additional factors weighted, Request a Custom Research Report. We review all feedback and publish material methodology changes in our weekly newsletter.

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