Grading in education is the process of applying standardized measurements for varying levels of achievements in a course. Grades can be assigned as letters (usually A through F), as a range (for example, 1 to 6), as a percentage, or as a number out of a possible total (often out of 100). In some countries, grades are averaged to create a grade point average (GPA). GPA is calculated by using the number of grade points a student earns in a given period of time. GPAs are often calculated for high school, undergraduate, and graduate students, and can be used by potential employers or educational institutions to assess and compare applicants. A cumulative grade point average (CGPA), sometimes referred to as just GPA, is a measure of performance for all of a student's courses. Yale University historian George Wilson Pierson writes: "According to tradition the first grades issued at Yale (and possibly the first in the country) were given out in the year 1785, when President Ezra Stiles, after examining 58 Seniors, recorded in his diary that there were 'Twenty Optimi, sixteen second Optimi, twelve Inferiores (Boni), ten Pejores.'" Yale later converted these adjectives into numbers on a 4-point scale, and some historians say this is the origin of the standard modern American GPA scale. Bob Marlin argues that the concept of grading students' work quantitatively was developed by a tutor named William Farish and first implemented by the University of Cambridge in 1792. That assertion has been questioned by Christopher Stray, who finds the evidence for Farish as the inventor of the numerical mark to be unpersuasive. Stray's article also explains the complex relationship between the mode of examination (oral or written) and the varying philosophies of education these modes imply to both the teacher and the student. As a technology, grading both shapes and reflects many fundamental areas of educational theory and practice. The A-D/F system was first adopted by Mount Holyoke College in 1897.