Los Angeles County letter grades (1998)
Los Angeles County began requiring restaurants to post A, B, or C letter grades based on health inspections, making scores visible at the door.
Studies found foodborne-illness hospitalizations in the county fell in the years after grading started.
The model spread to other cities and made public inspection grades a routine part of eating out.
Chicago uses the same transparency idea with Pass / Pass w/ Conditions / Fail grades, which is why this taqueria's inspection result is publicly known at all.
