Anchor paper

An anchor paper is a sample essay response to an assignment or test question requiring an essay, primarily in an educational effort. Unlike more traditional educational assessments such as multiple choice, essays cannot be graded with an answer key, as there is no strictly correct or incorrect solution. The anchor paper provides an example to the person reviewing or grading the assignment of a well-written response to the essay prompt. Sometimes a range of anchor papers are prepared, to provide examples of responses at different levels of merit.

Anchor papers are frequently used in standards based assessment, authentic assessment and holistic grading, where essay prompts are more common. They are especially used when grading essay responses on a mass scale, such as by graders working for the College Board.

Typically, only a few anchor papers are used for any particular grading project. Educators have commented that it is often difficult to match the diversity of responses against one or two papers, resulting in inconsistencies among graders working on the same project.

...
Wikipedia