Test results are reported as both a raw score and a scale score. The scale score is a student’s location on the Junior Science: Thinking with Evidence scale. All three tests use the same (JS) scale which is a continuum that represents increasing ability in ‘thinking with evidence’.
It is important to note that the JS scale is a different scale from the original Science: Thinking with Evidence (Year 7-10) tests. Scores cannot be compared between these two assessments.
Each scale score is presented with a margin of error. This is shown as a ‘plus or minus’ range and represents a band of scores within which you can be reasonably confident that a student’s achievement lies. For instance, a scale score of 49 +/- 3.9 jsc units means we can be reasonably confident that the student’s achievement level lies somewhere between 45.1 and 52.9 jsc units. The margin of error should be considered in all comparisons of scale scores, especially scores which are close together.
Every item in the Junior Science: Thinking with Evidence tests is also located on the JS scale.
The graph below shows the scale location of each item in the three tests. Question 1 in the first test (JS1), for example, is the easiest item overall; it has a JS scale location of 28.5 jsc units.
The distribution of items in each test on the JS scale
Using the JS scale enables some useful comparisons to be made
The difficulty of the items can be compared with a student’s achievement level on the scale
- e.g., the graph above shows a student, Aria, achieved a scale sore of 49.3+/- 3.9 jsc units sitting JS1. This is the same position as items 25 and 30 on the scale. She has a 50% chance of getting the answers to these questions correct. Aria’s chance of answering items correctly decreases as items with scale locations rise above her scale score, and increases as items with scale locations fall below her scale score.
The achievement of students in different year levels and sitting different tests can be compared
- e.g., a student in Year 5 sitting JS1 gets 22 out of 30 questions correct and is placed at 56 +/- 4.4 on the scale. Another student is in Year 6 sitting JS3 gets 16 out of 30 questions correct and also is placed at 55.9 +/- 3.9 on the scale. Because they have a similar scale score the two students have achieved the same level of ‘thinking with evidence’ even though they are in different year levels, sat different tests and had different raw scores
Students’ scale scores achieved at different time points can be compared, even though they may have sat different Junior Science: Thinking with Evidence tests
- e.g., a Year 4 student sitting JS1 achieves a raw score of 18 out of 30, which corresponds to a scale score of 49.2 +/- 4.0. Two years later he sits JS3 and gets a raw score of 18 out of 30 and a scale score of 59 +/- 4.0. Overall the student has shown an improvement in ‘thinking with evidence’.
- the achievement level of your class with that of each year level of a nationally representative sample
Next page: The norming study