<p>Andover appears to have an unusual grading system. If we assign A+ to a 6, A to 5.5 and A- to a 5, then over 45% of the students are in the A/A- category. That seems pretty inflated to me.</p>
<p>Another way to look at grade inflation is that it is another name for grade compression. It appears that teachers at Andover seldom assign grades of 0, 1, 2, or 3. Thus, grades seem to be compressed into three categories: 4, 5, and 6. And of those, 6 seems pretty rare.</p>