Seattle's emoji-based rating system grades restaurants on a curve

As they walk in the door, customers of the North Seattle restaurant "Joule" might notice a happy-face emoji along with an "excellent" health score rating -- a coveted symbol, signifying the gold-standard of healthy eateries. The rating is based on an average score from four surprise health inspections, compared to restaurants in the same ZIP code -- 98103.

But graded on a curve, if the same restaurant was put in the closest ZIP code (98133) the exact same score would have earned a rating of "good," compared to different scores of its neighboring eateries..

Click here for a searchable database of food ratings from other King County restaurants.

Since Seattle-King County Public Health rolled out their unique emoji-based restaurant ratings system 13 months ago, 45 inspectors have rated more than 6,900 restaurants, and each of those emoji signs was calculated with a mathematical curve formula -- also unique in the world -- which compares every restaurant's relative performance only to others in the same ZIP code.

That means for King County's 87 ZIP codes, there are 87 separate curve-calculations and breakpoints for what separates "Excellen" from "Good" to "Okay."

"We are doing something that's different, and we also think it's better," said Seattle-King County Public Health's James Apa. "Many other cities and counties are coming to us because they're interested in how we're doing this."

Apa says the curve is a fairer, more accurate way to rate restaurants, because it's based on years of data analysis and research by Stanford Law professor Dr. Daniel E. Ho, whose study revealed variations in scoring by health inspectors in the same agency. Dr. Ho's research revealed that two health inspectors in the same agency could see the exact same kitchen health code violation and disagree on how to score it 60 percent of the time.

The curve system -- in theory, corrects for differences among the viewpoints of different inspectors, each of whom is dedicated to a particular ZIP code -- and it's supposed to give customers a more consistent idea of how each restaurant is doing compared to its neighbors. Dr. Ho's research also suggests most people consistently dine within the same geographic area.

The top 55% of restaurants scores earn an "Excellent," meaning that restaurant had few or no red-critical health violations in the last four inspections. Thirty-six percent earn a "Good" rating, which indicates some red critical violations, and 9.5 percent are given an "Okay" rating, which indicates several red critical violations in the last four inspections.

Apa says one "excellent" effect the new emoji system, has been the new public urgency for restaurants to boast about having cleaner kitchens.

In the year since they launched the new rating system, restaurants with perfect scores went up from 52 percent to 55 percent. “We expect that trend to continue,” Apa said.

Cox Media Group