Overview

Every rubric has an associated scale upon which the scoring of the rubric is based.  The creation of the scale cannot occur until the focus of the rubric has been determined.

The scale should include the range of possible performances arranged in order from best to poorest performance.  The range of performance is then divided into various levels of performance.  The number of divisions made should be based on the ability to clearly separate the various performance levels.  Doing so helps assure that the scale can be reliably rated.  That is, the ratings made using the scale are consistent across time and across raters.  Without such consistency, the ratings made with scale cannot be trusted.

Elements of a Rubric Scale

Most rubrics contain two separate elements:  a set of labels that describe each of the performance levels and an associated set of scores.

Here is an example of a commonly used scale in music performance.

 

Labels	Score
Excellent	20
Good	15
Fair	10
Poor	5

This scale has a number of characteristics that should be noted.  First, the labelss do form a readily understood continuum of the total range of possible performances.  However, they are not very informative as to what a rater should attend when rating nor do they provide much information to a student who would like to improve.  It should be pointed out that this is probably why ratings at performance festivals are usually always in the Excellent to Good range.  Rarely, are any scores below this.  This brings into suspicion the validity of such a scale.

Another characteristics of the scale is that the scores are even divisions in multiples of 5.  The weight of which is more for the excellent performance.  Notice that the even division implies that there is an even amount of skill required to change performance levels.  This is probably not reflective of the real world.  Early attempts at music performance can quickly achieve the fair level.  Moving to the good and then to the excellent levels requires ever greater development of musical skills.

Labels

The labels chosen to indicate the various performance levels can have a tremendous influence on how the scale is rated and the connotations a student's performance level has.  Consider the modifications to the labels used in the scale above.

 

Labels	New Labels
Excellent	Professional
Good	Developing
Fair	Beginning
Poor	Immature

Notice how the new labels completely change the "feel" of the scale.  This will have dramatic effects on how the scale is used and interpreted by those who use it:  the teacher, other adjudicators, and students.  The terms selected to describe the various performance levels should be chosen so that they do not have negative connotations if the purpose is to inform with an eye on future improvement.

Here is another generic set of Labels that can be used in place of the original.

 

Labels	New Labels
Excellent	Above Grade Level
Good	At Grade Level
Fair	At Start of this Grade Level
Poor	Below Grade Level

This set of labels is based on an average level of performance for the particular grade of the student.  The performance level of a 10th grade student is dramatically different than that of a 5th grade student.  This must be taken into account when such labels by both those doing the rating and those interpreting the rating.

Scale Scores

The values assigned for the various performance levels of a rubric should reflect what is entailed to perform at any given level, the labels used to define the scale, and the nature of the trait being measured.  The scores can be used to weight the value of a performance.  Consider the following two score systems.
 

Labels	Unweighted Scores	Weighted Scores
Professional	20	20
Developing	15	12
Beginning	10	6
Improving	5	2

The unweighted scores have equal divisions of 5 points between each of the possible performance levels.  The weighted scores change as you move from the lowest level to the highest level of performance such that the divisions between the levels increase.  The differences between the levels for the weighted scores are 4, 6, and 8.  This gives more credit for achieving ever higher levels of performance.

The following takes the two scales above and allows a range of scores to be assigned for each level.  This provides the adjudicator with the ability to differentiate individuals within each of the levels.

The scale scores chosen for a particular rubric should be selected to reflect the importance that is placed on the trait being assessed and on the levels of performance for the trait.