How SafeDine scores work.

Which method is used today

SafeDine is moving sources from method 3.0 to 4.0 one source at a time. Until a source moves, its scores use 3.0, including its age deduction of up to 25 points. No score has been silently recalculated.

Scores from these agencies still use 3.0: NYC Department of Health and Mental Hygiene, New York State Department of Health, Wake County Environmental Health, Chicago Department of Public Health, Delaware Division of Public Health, Cincinnati Health Department, Detroit Health Department, East Baton Rouge Parish Health Unit and Boston Inspectional Services.

The formula and worked example below describe 4.0. Under 4.0, inspection age appears beside the score and does not lower it. Official agency grades and inspection dates are separate from either SafeDine method.

The formula

Score = 100 − finding deduction

The finding deduction is the points lost for what inspectors cited, averaged across up to three recent inspections and weighted toward the newest.

Under method 4.0, age is not part of the number. A score shows the date of the latest inspection it rests on, so you can see how recent the evidence is. The result is rounded to a whole number and kept between 0 and 100. Only inspection records go in: diner reviews and incident reports are not part of the calculation.

What each finding costs

Each finding in the agency record is classed as high priority, intermediate or basic. High-priority findings could directly cause foodborne illness, intermediate findings could lead to a high-priority problem if left unaddressed, and basic findings concern best practice. Where the agency publishes that class, SafeDine uses it; where it does not, the class comes from SafeDine’s own tables, and the restaurant’s profile says which.

SafeDine subtracts a fixed number of points per finding. A high-priority finding that SafeDine classifies as a risk factor costs the most. Where the agency publishes that designation it is used; elsewhere the classification is SafeDine’s model.

Corrections and repeat findings

When the agency’s record says a finding was corrected during the inspection, SafeDine gives back 50% of its points. A correction the record does not place in the inspection itself, such as an item marked passed at a later visit, earns nothing: SafeDine does not infer when a correction happened. The record counts corrections rather than naming them, so the credit is shared evenly: with 1 of 4 findings corrected, the inspection gets back 50% of a quarter of its finding points.

A finding repeats when the same violation code was cited at an earlier inspection that also counts. Because at most three inspections count, a finding can have at most two earlier citations. Each one adds 25% of that finding's points, rounded to whole points, so a repeated risk-factor finding costs 4 extra points after one earlier citation and 8 extra after two. When the record does not say how serious the repeated finding is, it is counted as intermediate. The correction credit never reduces repeat points.

Which inspections count

Up to 3 inspections count: the most recent ones from the last 48 months. An inspection with a missing, invalid or future date, or without complete finding counts, is set aside rather than guessed.

An inspection more than 48 months (4 years) old never counts. When a restaurant’s latest inspection is that old, SafeDine shows its inspection history but no score, and a score is withdrawn on the day its latest inspection passes 48 months.

Each counted inspection gets a weight: its place in line, times its age, times its type. The finding deduction is the weighted average of the inspections, so weights decide how much each inspection counts compared with the others. A single inspection counts in full.

How current the evidence is

Every score shows two dates. The inspection date is when the agency last inspected the restaurant. The “as of” date is when SafeDine last retrieved the agency’s record.

A score stays visible with its “as of” date until the latest inspection is more than 48 months old, and is withheld after that. Some sources have not been refreshed for several weeks, so check the “as of” date. The latest official inspection always stays visible; earlier inspection history is part of a paid plan that is not open yet.

A worked example

Two routine inspections count. The newer one, 4 months before the score was calculated, cited one high-priority finding classed as a risk factor and two basic findings, and the agency recorded one of the three as corrected during the inspection. The older one, 11 months before, cited one intermediate finding that is not a repeat.

The numbers below are produced by the same code that scores every restaurant.

Newer inspection

15 + 2 + 2 = 19 points. The correction returns 3 (a third of 19, halved, rounded), leaving 16.

Older inspection

5 points.

Weights

Newer: place 1.0 × age 1.0 × routine 1.0 = 1.0. Older: place 0.6 × age 0.9 × routine 1.0 = 0.54.

Finding deduction

(16 × 1.0 + 5 × 0.54) ÷ 1.54 = 12.1, the weighted average.

Score

100 − 12.1 = 87.9, shown as 88. Grade A.

Trend

Scored alone, the newer inspection is 84 and the older 95: down 11 points, so declining.

Confidence

Medium: two inspections count and the newer one is less than 12 months old.

Grades, trend and confidence

Scores map to three grades: 85 or more is an A, 70 to 84 is a B, and below 70 is a C.

Trend compares the counted inspections scored one at a time, before weighting. With three inspections, the latest change counts twice as much as the one before it. A change of more than 5 points up reads as improving, more than 5 down as declining, and anything in between as stable. With a single inspection there is no trend.

Confidence is high when three inspections count and the latest is at most 6 months old, medium when at least two count and the latest is at most 12 months old, and low otherwise.

What violations mean

Health inspection language is dense. SafeDine groups findings into three practical concerns diners can understand, and the score treats each group differently.

Food handling: temperature, storage and contamination findings such as hot holding, cold holding and cross contamination. When one is classed as a risk factor, by the agency where it publishes that designation and otherwise by SafeDine’s model, it carries the heaviest per-finding weight in the SafeDine score.

Hygiene: hand washing, glove use and sanitizing findings about the people and surfaces that touch food, including sink access and sanitizer strength.

Facility condition: maintenance findings such as equipment, surfaces and pest context. They matter when they affect cleanliness or safe operations.

A finding describes conditions observed during an official visit. Priority, correction status, recurrence and the authority’s own disposition determine its practical context.

Transparency

Every published score points back to the inspection history it came from.

• Source agency
• Inspection date
• Violation text