Under this method certain categories of abilities are defined in advance such as excellent, verygood, average, poor, very poor, outstanding etc.

The answer should be graphic rating scale. A grading scale, on the other hand, is a system used to categorize student performance, often using letter grades (A, B, C, D, F)
A graphic rating scale is a performance appraisal method where supervisors rate employee performance on a scale for specific traits or behaviors. It typically uses a continuum, such as a numerical scale (e.g., 1-5) or descriptive labels (e.g., "Excellent," "Good," "Average," "Fair," "Poor"), to indicate the level of performance.