Workshop grading strategies

Simply said, selected grading strategy determines how the assessment form may look like and how the final grade for submission is calculated from all the filled assessment forms for the given submission. Workshop ships with four standard grading strategies. More strategies can be developed as pluggable extensions.

Accumulative grading strategy

In this case, the assessment form consists of a set of criteria. Each criteria is graded separately using either a number grade (eg out of 100) or a scale (using either one of site-wide scale or a scale defined in a course). Each criterion can have its weight set. Reviewers can put comments to all assessed criteria.

When calculating the total grade for the submission, the grades for particular criteria are firstly normalized to a range from 0% to 100%. Then the total grade by a given assessment is calculated as weighted mean of normalized grades. Scales are considered as grades from 0 to M-1, where M is the number of scale items.

$G_{s}={\frac {\sum _{i=1}^{N}{\frac {g_{i}}{max_{i}}}w_{i}}{\sum _{i=1}^{N}w_{i}}}$

where $g_{i}\in \mathbb {N}$ is the grade given to the i-th criterion, $max_{i}\in \mathbb {N}$ is the maximal possible grade of the i-th criterion, $w_{i}\in \mathbb {N}$ is the weight of the i-th criterion and $N\in \mathbb {N}$ is the number of criteria in the assessment form.

It is important to realize that the influence of a particular criterion is determined by its weight only, not the grade type or range used. Let us have three criteria in the form, first using 0-100 grade, the second 0-20 grade and the third using a three items scale. If they all have the same weight, then giving grade 50 in the first criteria has the same impact as giving grade 10 for the second criteria.

Comments

The assessment form is similar to the one used in accumulative grading strategy but no grades can be given, just comments. The total grade for the assessed submission is always set to 100%. This strategy can be effective in repetitive workflows when the submissions are firstly just commented by reviewers to provide initial feedback to the authors. Then Workshop is switched back to the submission phase and the authors can improve it according the comments. Then the grading strategy can be changed to a one using proper grading and submissions are assessed again using different assessment form.

Number of errors

In Moodle 1.x, this was called Error banded strategy. The assessment form consists of several assertions, each of them can be marked as passed or failed by the reviewer. Various words can be set to express the pass or failure state - eg Yes/No, Present/Missing, Good/Poor, etc.

The grade given by a particular assessment is calculated from the weighted count of negative assessment responses (failed assertions). Here, the weighted count means that a response with weight $w_{i}$ is counted $w_{i}$-times. Course facilitators define a mapping table that converts the number of failed assertions to a percent grade for the given submission. Zero failed assertion is always mapped to 100% grade.

This strategy may be used to make sure that certain criteria were addressed in the submission. Examples of such assessment assertions are: Has less than 3 spelling errors, Has no formatting issues, Has creative ideas, Meets length requirements etc. This assessment method is considered as easier for reviewers to understand and deal with. Therefore it is suitable even for younger participants or those just starting with peer assessment, while still producing quite objective results.

Rubric

See the description of this scoring tool at Wikipedia. The rubric assessment form consists of a set of criteria. For each criterion, several ordered descriptive levels is provided. A number grade is assigned to each of these levels. The reviewer chooses which level answers/describes the given criterion best.

The final grade is aggregated as

$G_{s}={\frac {\sum _{i=1}^{N}g_{i}}{\sum _{i=1}^{N}max_{i}}}$

where $g_{i}\in \mathbb {N}$ is the grade given to the i-th criterion, $max_{i}\in \mathbb {N}$ is the maximal possible grade of the i-th criterion and $N\in \mathbb {N}$ is the number of criteria in the rubric.

Example of a single criterion can be: Overall quality of the paper with the levels 5 - An excellent paper, 3 - A mediocre paper, 0 - A weak paper (the number represent the grade).

There are two modes how the assessment form can be rendered - either in common grid form or in a list form. It is safe to switch the representation of the rubric any time and it is better to actually try it than to read a description here :-)

Note on backwards compatibility: This strategy merges the legacy Rubric and Criterion strategies from Moodle 1.x into a single one. Conceptually, legacy Criterion was just one dimension of Rubric. In Workshop 1.x, Rubric could have several criteria (categories) but were limited to a fixed scale with 0-4 points. On the other hand, Criterion strategy in Workshop 1.9 could use custom scale, but was limited to a single aspect of assessment. The new Rubric strategy combines the old two. To mimic the legacy behaviour, the old Workshop are automatically upgraded so that:

• Criterion strategy from 1.9 are replaced with Rubric 2.0 using just one dimension
• Rubric from 1.9 are by Rubric 2.0 by using point scale 0-4 for every criterion.

In Moodle 1.9, reviewer could suggest an optional adjustment to a final grade. This is not supported any more. Eventually this may be supported in the future versions again as a standard feature for all grading strategies, not only rubric.