How We Score Buildings
Our algorithm analyzes 70+ million public records across 25 data sources to produce one comprehensive score for every building in New York City. Here's what goes into it.
Before you sign a lease, know what you're walking into.
Covering every building in New York City
The Grading Scale
Every building receives a score from 0 (best) to 100 (worst), mapped to a letter grade. Lower is better — think of it like a risk score.
Minimal or no issues on record. Well-maintained with a strong compliance history.
Some minor issues, nothing unusual. Typical for a reasonably managed building.
Mixed record worth reviewing. Patterns may be emerging across one or more components.
Multiple unresolved issues across several dimensions. Declining trajectory.
Serious violations, safety concerns, or systemic neglect. Immediate attention warranted.
The Seven Scoring Dimensions
Each building's score is composed of seven scoring dimensions. The weights reflect each dimension's predictive importance — developed through extensive analysis of building outcomes across all five boroughs.
Living Conditions
Are residents living in safe, code-compliant conditions?
Building Safety
Is the building structurally sound with up-to-date safety compliance?
Complaint Burden
How often do residents and neighbors report issues — and are the patterns meaningful?
Management Quality
Is the building properly registered, responsive to issues, and meeting regulatory requirements?
Financial Health
Does the owner have the financial capacity to maintain the property?
Maintenance History
Is there evidence of proactive upkeep and passing inspections?
Legal & Enforcement
Has the building faced litigation, enforcement actions, or emergency orders?
Recent Improvements
We continuously refine our algorithm to be fairer and more accurate. Here are the latest improvements to how we calculate scores.
Time Decay
Records are weighted by recency. A violation from last month counts more than one from a decade ago. Default half-life is two years; longer for things like facade issues that persist.
Severity Tiers
Each violation is classified into one of four severity tiers (Critical / High / Medium / Low) based on NYC's own definitions and tenant-safety impact. The full taxonomy is published in our codebase.
Peer-Group Normalization
Scores are computed against similar buildings (size and pre-war vs. post-war era), so a 5-unit walkup isn't compared to a luxury high-rise.
Limited Data Indicator
Buildings with insufficient public records now display a Limited Data badge instead of receiving a potentially misleading score.
Peer-Group Comparison
A 6-unit pre-war walkup shouldn't be compared to a luxury high-rise. We compare buildings against similar properties so every score reflects realistic expectations for that category of building.
Each building's score is contextualized against similar buildings by size and age (pre-war vs. post-war), so you can see whether it's performing above or below its peers.
Data Sources
We ingest data daily from 26 official public sources. Every building in NYC is covered — not a sample, not a subset.
We also maintain historical snapshots of every building over time. This allows us to track score trajectories — whether a building is improving or declining — data that doesn't exist anywhere else.
Frequently Asked Questions
Why does my building have a low score?
Health scores reflect the cumulative impact of multiple risk signals across seven scoring dimensions. A low score typically indicates a pattern of unresolved issues. Check the building's score breakdown to see which areas are driving the score.
Can I dispute a score?
Our scores are calculated from official public data sources. If you believe there's a discrepancy, contact us at data@openstoop.com with the building address and details. We investigate every report.
How often are scores updated?
Our data pipeline ingests new information daily from 25 public sources. Scores are recalculated regularly to reflect the latest available data.
What makes OpenStoop different from other tools?
Most tools show you raw violation lists. We synthesize 25 data sources into one score that factors in severity, recency, patterns, and context — so you don't have to. We also track how buildings change over time.
What does 'Limited Data' mean?
Some buildings have very few public records — new construction, small buildings, or properties that simply haven't generated much regulatory activity. Rather than assign a potentially misleading score, we flag these with a Limited Data indicator.
How do I get started?
Search any NYC address to instantly view its building health score and key data. No account required.