Nearly four in 10 Boston restaurants racked up enough food safety violations during an inspection last year to earn the lowest possible letter grade under the city’s forthcoming rating system.
But, within a matter of days or weeks, virtually every one of the restaurants corrected enough violations to bring their marks up to the highest letter grade.
The new rating system, which will rate the restaurants “A,” “B,” or “C,” has yet to go into effect. But the Globe used publicly available inspection records, and the grading formula the city recently announced it intends to use, to calculate the letter grades that restaurants across Boston would have received.
The Globe focused on 2015, the most recent full year of data. It found:
• A total of 1,127 restaurants, or about 37 percent, of the city’s 3,000 dining establishments — including sit-down restaurants, takeout spots, and food trucks — earned the equivalent of a C for at least one food safety inspection.
• For another 695, or 23 percent, of the city’s restaurants, the lowest grade earned during any inspection was the equivalent of a B.
• The rest, 1,191, or nearly 40 percent, earned the equivalent of straight A’s for the year.
Despite that range of performance, people can expect to see mostly A’s posted on the city’s website and in restaurant storefronts when letter grades go up on the Web this year and in store windows in 2017.
That’s because restaurants that get B’s and C’s on initial inspections, which are unannounced, typically improve their grades to A’s on their next inspections, which are scheduled soon after. City inspection records show that virtually every restaurant, 99.4 percent, eventually earned the equivalent of an A at some point during 2015.
What’s more, restaurants that get a B or C on initial inspections will not be required to immediately post those grades in their storefronts, nor will the city post them online, said William Christopher, head of Boston’s Inspectional Services Department. Instead, he said, such restaurants will get one reinspection, within 30 days, to try to boost their grades before they are displayed publicly.
Behind the scenes, Christopher said, there will be incentives for restaurants to get an A on the first try.
Those that get an A on initial inspection can expect their next unannounced visit within about a year; those that get a B, within about six months; those that get a C, within about three months.
“We’re hoping that will be an incentive for restaurants to want to get an A” the first time, said Christopher.
If a restaurant fails to earn an A after both the initial inspection and the second inspection, its B or C will be displayed publicly. City inspectors will keep working with it to bring it into compliance and educate workers on best food safety practices.
To boost its grade at this point, the restaurant would have to pay the city $300 for a third inspection. The restaurant can also pay $300 for a fourth inspection, but its grade after that will be permanent until the next inspection cycle.
City officials say they hope the system will also encourage restaurants to move swiftly to correct violations.
“We have noticed in the past that we have visited some establishments numerous times before they are in compliance,” said an e-mail from ISD spokeswoman Lisa Timberlake. “Repeat visits are time consuming and take inspectors away from other inspections.”
“The end goal is for all restaurants to end up with an A grade,” she said.
While the rating system will be new, it will not cost the city any extra money because the process for inspecting restaurants will not change, officials said. And complaints about food safety will continue to prompt immediate city inspections.
“We’re just changing the way inspections are presented publicly so it’s more transparent and easier for consumers to understand,” said Christopher.
The city will use a numerical system to calculate the letter grades, with a top score of 100 and deductions for each infraction, but the city will not post numerical scores. That means C grades, which are 80 or below, could cover anywhere from 80s to much smaller numbers, even negative numbers.
The department expects to launch a pilot version of the rating system as soon as next month, pending City Council approval.
Once it launches, grades will be posted on a rolling basis on the city’s website. After the first year of grading, restaurants will be required to post in their storefronts the grades they received.
Boston’s program will resemble rating systems that New York, Los Angeles, and other cities have been using since as early as the late 1990s. Locally, Newton launched a similar program in the fall that requires numerical ratings to be displayed inside restaurants.
The practice of grading restaurants has faced criticism elsewhere, including skepticism over whether the ratings lead to improved conditions, and concerns that the ratings can be arbitrary and unfair.
Local restaurant industry leaders have worried Boston’s system could be unfair to restaurants.
The city consulted with the Massachusetts Restaurant Association to develop the new rating system.
“Food safety is every restaurant operators’ first priority,” said a recent statement from Bob Luz, the association’s president and chief executive.
Still, he cautioned, “A health inspection represents a single snapshot in time and there will need to be an educational component to the dining public in regards to this new system. We are thankful to the city for engaging in a thoughtful dialogue and exchanging of ideas to address the concerns that undoubtedly will arise as a result of changing to a letter grading system.”