Index


Table 6
.

Table 6 is the Facets "Rulers", which is a graphical display of student ability, rater severity, and item difficulty on a common logit scale. This is the easiest part of the output for non-specialists to grasp, so is very useful for communicating overall results. In this example, mean item difficulty and rater severity are set to 0.0 logits and student ability is allowed to "float". We can see that students are mostly 3 or more logits "higher" than the mean of raters and items, so this assessment was much too easy for these students. Either the raters were much too lenient, or the items were much too easy.

 

We can also see that "Gestures" was the most difficult item, while "Introduction" was very easy. The rating scale is shown on the right hand side. We can see that the interval between 0 and 1 is very small, while the interval between 2 and 3 is much larger, showing that the raw ratings are not equal interval measures of ability.

 

Table 6.0  All Facet Vertical "Rulers".
 
Vertical = (1*,2*,3A,S) Yardstick (columns lines low high extreme)= 0,7,-2,5,End
+--------------------------------------------+
|Measr|+Students|-Raters|-Items        |Scale|
|-----+---------+-------+--------------+-----|
|   5 +         +       +              + (3) |
|     |         |       |              |     |
|     | *       |       |              |     |
|     | *       |       |              |     |
|     | *       |       |              |     |
|     | *       |       |              |     |
|     |         |       |              |     |
|   4 + **      +       +              +     |
|     |         |       |              |     |
|     |         |       |              |     |
|     | *       |       |              |     |
|     |         |       |              |     |
|     | *       |       |              |     |
|     | *       |       |              |     |
|   3 + *       +       +              +     |
|     | **      |       |              |     |
|     |         |       |              | --- |
|     |         |       |              |     |
|     |         |       |              |     |
|     |         |       |              |     |
|     | **      |       | Gestures     |     |
|   2 +         +       +              +     |
|     |         | *     |              |     |
|     |         | *     |              |     |
|     |         | *     |              |     |
|     |         |       |              |     |
|     |         |       |              |  2  |
|     |         | *     | Eyes         |     |
|   1 +         +       +              +     |
|     |         |       |              |     |
|     |         |       |              |     |
|     |         |       | Preparation  |     |
|     |         | *     |              |     |
|     |         |       |              |     |
|     |         | *     |              |     |
*   0 *         * *     * Length       *     *
|     |         | *     | Overall      | --- |
|     |         | *     | Conclusion   |     |
|     |         |       |              |     |
|     |         | **    | Explanations |     |
|     |         |       | Topic        |     |
|     |         | *     | Structure    |     |
|  -1 +         +       +              +     |
|     |         | *     |              |     |
|     |         |       | Introduction |  1  |
|     |         | *     |              |     |
|     |         |       |              |     |
|     |         |       |              |     |
|     |         | *     |              |     |
|  -2 +         +       +              + (0) |
|-----+---------+-------+--------------+-----|
|Measr| * = 1   | * = 1 |-Items        |Scale|
+--------------------------------------------+