One test of the quality of ratings is interrater agreement. A high level of degree of agreement is indicative of objectivity of ratings. Another test of quality is consistency in a particular rater's judgments over time. Ratings should not drift but rather should remain anchored to carefully defined points on the scoring scale. When these standards are met, it becomes possible to take advantage of the immense power of this kind of assessment to muster concrete evidence of improvement in student performance over time.
Scores can be holistic or analytical, considering criteria together as a whole or separately.
The choice is a function of the assessment purpose. Purposes like diagnosing weaknesses in student performance that require a high resolution microscope require analytical scoring. Recording system alternatives include checklists of attributes present or absent in performance, rating scales reflecting a range in performance quality, anecdotal records that describe performance or mental record keeping. Each offers advantages and disadvantages depending on the specific assessment context. Raters of performance can include the teacher, another expert, students as evaluators of each other's performance or students as evaluators of their own performance.