Certificates were issued to schools when they advanced (or occasionally lowered) their grading sequence. Through 1927 the official designation of grade sequences was determined by the number of years of approved instruction offered beyond the eight grade: junior high (1 year), middle high (2 years), senior high (3 years), high (4 years), academy (4 years in a chartered or incorporated private school - this designation was dropped in favor of high school in 1913). In 1928 an amendment to the Regents Rules changed the designations as follows: junior high (grades 7 - 9), middle high 1/2/3 (grades 9, 9-10, or 9-11, respectively), high (grades 9 - 12 to 7 - 12). The designation senior high was discontinued. A further amendment in 1937 eliminated the designations of middle high 2 and 3.
From the description of Register of Advance-in-grade certificates issued to secondary schools, 1906-1967. (New York State Archives). WorldCat record id: 83091713
