Scoring factor
How to weight school quality
Weight schools for the years you will actually use them. A high weight is how a district beats a cheaper house. A low weight keeps the rating visible without letting it decide.
How hard to weight it
If you are buying because of the schools, this factor should be the largest weight, in the high 20s or low 30s. The growing-family preset puts it at 30. Below about 10, a 40-point school gap moves the total by fewer than 4 points, which is a tie-breaker, not a decision.
Leave it above zero even if you have no children. A zero hides the number. Four points, which is what the commute and downsizing presets use, keeps the rating on the report and almost never changes which house ranks first.
Do not raise it to “be safe” if you will be gone before a child reaches the school you are paying for. You would be scoring a district you will not use, and giving up condition or value to do it.
What the weight does to the total
Two houses, school scores 90 and 50. The gap in the total depends only on the weight.
| Weight | Effect on the total |
|---|---|
| Weight 30 | 12-point gap. Schools can beat a large value difference. |
| Weight 10 | 4-point gap. A modest value or commute edge erases it. |
| Weight 4 | 1.6-point gap. The rating is on the report and rarely reorders the list. |
The property score is the weighted sum: each factor score times its weight, divided by 100. Weights are scaled to add up to 100 before that sum.
What the score uses
By default an analysis uses the formulas in “What the score uses.” The new scoring engine runs only when FEATURE_USE_NEW_SCORING_ENGINE is on, or when a rollout percentage includes that account. Where that engine differs, it is called out separately. A missing input scores 50. That is a neutral, not a zero, and it can outrank a known weak result.
The score is the listing’s school rating on a 1–10 scale, multiplied by 10. A 9 becomes 90. A 6 becomes 60.
When you paste a Zillow URL, that rating is the listing’s own figure if it has one. If it does not, RAAM averages GreatSchools ratings on the scraped schools list, using the zoned schools when any of them are rated, and otherwise the nearby rated schools. The average is rounded to one decimal, then multiplied by 10.
If there is still no rating, the default engine uses a fixed rating stored for a short city list: Boston, Cambridge, Somerville, Arlington, Lexington, Newton, Brookline, Medford, Watertown, Belmont, Waltham, Malden, Everett, Revere, Chelsea, Denver, Phoenix, Austin, Los Angeles, and Naples. Lexington and Newton are stored as 10, so a house there with no listing rating scores 100. Chelsea is stored as 4 and scores 40. Any other city scores 50.
Those stored ratings are reference numbers in the code, not a live pull of test scores. Confirm the district yourself before you treat a 100 as this year’s schools.
score = (rating ÷ 10) × 100
No rating and no listed city → 50
When the new engine is on
When the new engine is on and the listing still has no rating, the census path estimates schools from the tract: median income scaled from $30,000 to $150,000 (60%) plus the poverty rate flipped across 0–30% (40%). Confidence is low, and the result carries a warning to verify schools directly. It does not look up a district.
The public overview is the methodology page. Where that page says comparables, orientation, or documented updates, the formulas on this page are the ones that run.
Tradeoffs against the other factors
- Value for money
A famous district is often the expensive side of the value score. At school weight 30 and value weight 15, a 40-point school advantage is worth 12 points and a 40-point value advantage is worth 6. The district wins unless the price gap is much wider than the school gap.
- Lot size
Families often want both. The schools-and-yard preset puts the yard second, at 20, so a small lot in a top district still loses to a larger lot in a slightly weaker one if the lot gap is big and the school gap is small.
- Commute
The towns stored with the highest school ratings are also stored with longer commutes. Weighting schools up and commute down is a real choice, not a free upgrade.
Mistakes that move the ranking
- Treating 50 as “average schools.” Outside the city list, 50 means the listing had no rating. A strong unlisted district and a weak one look the same.
- Assuming the score read renovation, class size, or a specific school your child would attend. It is one rating, preferring zoned schools when the scrape includes them.
- Cranking the weight because a town is “known for schools,” then comparing houses inside that same town. They will all score alike, and the weight will do nothing to separate them.
Profiles that lean on this
The other six factors
Set the weight yourself
The builder opens on an even split, or on the platform default if one is saved. It does not assume this factor. If you want a whole profile filled in, start from a buyer preset.
Build your analyzer