Recently, a new pizzeria opened near where Anna Tepi lives in the Bronx. It boasted a crisp, blue A health rating in the window. So Tepi, 18, tried a slice: “It’s a good restaurant, didn’t make me sick.”

But a few weeks later, she walked by and noticed that the A had been replaced by a B. Tepi, 18, considered her trips to the pizzeria. “It was clean, but I don’t know. Maybe it was the kitchen.” She hasn’t been back.

It’s a familiar feeling for New Yorkers since Mayor Michael Bloomberg instituted the letter grading system six summers ago. Seeing the telltale green B, or even the dreaded (but still) passing C. Then either searching for one of NYC’s approximately 24,000 other restaurants or taking the low-grade plunge.

Last week, Boston’s City Council approved a measure that, pending mayoral approval, will create that city’s own A-B-C system, much like New York’s.

If its rollout is anything like NYC’s, the system’s development will be marked by controversy, even as residents get used to either processing or ignoring the new information, no matter how valuable it actually is.

Letters to live by

The restaurant ratings were part of Bloomberg’s efforts to use government to encourage good behavior: from curtailing smoking to an attempted soda ban. In this case, the goal was to encourage dirty restaurants to clean up their act.

Many restaurant owners were up in arms about what they saw as harassment, worried (with good reason) that anything but an A would result in decreased business.

In 2012, the City Council agreed to hold hearings on the issue. Bloomberg blasted back, arguing that salmonella rates had decreased; that a survey said New Yorkers liked and used the letter grades; and that restaurant profits had gone up. “The proof is in the pudding,” Bloomberg said, culinarily.

Since then, A ratings have increased and the state’s major restaurant association has lessened much of its opposition. The Department of Health and Mental Hygiene celebrated a five-year anniversary of the letter system last year, saying the 95 percent of restaurants then receiving As meant a healthier city, and noting a continued decline in salmonella cases.

But questions about the efficacy of the ratings have lingered. Reviews of the underlying inspection data — including one NYU study completed this winter — suggest restaurants are being graded on a curve. Officially, to get an A a restaurant must have fewer than 14 “points” for violations including incidences of rodents or food prepared at insufficiently hot temperatures. But the study found restaurants received low A scores at a significantly higher rate than high Bs. DOH has pushed back on the idea of inflated grades.

Last week, 21,701 restaurants had an A rating; 1,547 had a B; with 221 at C and 751 pending, according to DOH data.

Daniel Ho, a Stanford Law School professor who has studied the efficacy of inspection, identifies two basic challenges to health inspection programs. One is grade inflation, an even larger problem in San Diego, for example, where out of 9,000 restaurants inspected in 2011, only eight had less than an A.

The other problem, much more apparent in NYC, was a “high level of inconsistency in how individual inspectors carry out an inspection.” In his 2012 Yale Law Journal study on the issue, Ho found that an inspector’s score from a routine inspection had “no substantive predictive power over how that same establishment was going to fare in the next unannounced inspection,” he says.

A spokesman for the New York State Restaurant Association mentions “consistency” in inspections as the one major continued “kink” in the system.

The future of letter grading

Ho, who is researching health inspection in Washington’s King County (which includes Seattle), says that inspectors peer-reviewing fellow inspectors has been found to increase consistency.

In a statement the DOH said the letter grading system has led to greater compliance with food safety and sanitary standards.

With about 60 percent of restaurants earning an A grade on their first inspection, and more than 90 percent posting A grades in their windows overall, we can confidently say the restaurant grading system has been a boon for restaurants and diners alike," a spokeswoman said. 

For many New Yorkers surveyed informally Friday, the letter system has become a fact of life, whether or not it correlated to better health.

Some were rigid in their consideration: “Even grade pending freaks me out,” said Giuliana Cappiello, 24. “I want the security of an A.”

Others acknowledged that B or C didn’t mean that the food was necessarily dangerous (both are passing grades), given the wide range of violations that can drag down a grade. Indeed, for a brief moment in 2014, the luxurious Per Se groveled with enough violation points to earn a C rating.

Carl Clayton, 28, for example, described feeling nonplussed about the B rating for a favored restaurant in Brooklyn. (Its three violations include a hot food item not served hot enough, food not being cooled by an approved method and a supervisor of food operations who lacked a food protection certificate).

“From outside they look clean,” Clayton said, adding that he’d never gotten a stomach ache from the Latin American food served on site.

“The food is good, always fresh,” he said, smiling. His companion, Tamika Wilson, murmured assent. “I have to go over there someday,” she said.