1. Primary Analysis Method
Comparison of Achieved (HSC) results with Typical
This powerpoint file gives an overview of the Primary Analysis method presented in the HSC Analysis of Results.
The primary analysis is a comparison of the results in each subject with what is typical of comparable students in the School Certificate.
The account of the process given in this presentation contains some over-simplifications, but does give the general thrust of what has been done.
© JS DeCourcy 2004

2. How have our students gone in the HSC, compared with comparable students in other Catholic schools?

3. Question 2:
What – if anything – does this tell (or ask) us about how teaching and learning are going in our school?

4. What are we going to do about it?
Question 3:
What are we going to do about it?

5. Comparison of Achieved with Typical
When people start considering HSC results, they often come to the task with a concept of “what would be expected for this group”. Often the assumption is that the group should be about State Average. This may or may not be a valid assumption. But at least in their statements - “This wasn’t a very good group” – they are implying a statement of expectation. The consideration of the results is then one of what has been achieved compared with what was expected.
I used to use the idea of “Expected” but changed it to “Typical” on the argument that “I expect my students to be better than just the same as the students in other catholic schools…”
The primary analysis takes this achieved/typical concept and makes it explicit.
Typical

6. Comparison of Achieved with Typical
To begin the analysis, SC results from two years ago are obtained for as many as possible of the individual students represented in the analysis. The “normal” score of each student’s English-literacy, Mathematics, Science and (when available) HSIE score is obtained, and weighted for each HSC subject.
SC for all state 2 yrs ago
Typical

7. Comparison of Achieved with Typical
The SC aggregate normal scores are extracted for just those students taking one particular HSC subject. For the sake of the example, let’s say we are considering Biology. The blue line represents the distribution of SC aggregate normal scores for students doing Biology this year.
SC for this HSC subject
Typical

8. Comparison of Achieved with Typical
From the group of all students in the analysis doing Biology, extract just those doing Biology in this particular school. For the sake of making a pointed example, the green band here suggests that in this particular school the Biology students had much lower SC scores two years ago than was typical of Biology students this year across the state. (The middle of the green band is considerably to the left of the middle of the blue band.)
SC for this HSC subject at this school
Typical

9. Comparison of Achieved with Typical
Average of SC for this HSC subject
in this school
Find the average of the SC aggregate scores for the students in this school. Remember that the calculation of the average is never an absolute process – such a calculation always includes some assumptions about the nature of the measurement. Therefore………
Typical

10. Comparison of Achieved with Typical
…….. calculate the uncertainty of measurement of the average, to give a range within which it is 95% probable that the average will lie.
95% probability range for average
Typical

11. Comparison of Achieved with Typical
HSC results for whole study in this subject
Achieved
Then consider the HSC results for all students in the analysis in Biology (which we start with as one-unit marks).
Typical

12. Comparison of Achieved with Typical
Re-scaled HSC results for whole study in this subject
Achieved
Re-scale the Biology marks to the same mean and SD as the SC results for those students when they did the SC two years earlier. The two blue lines now have the same mean and SD; the HSC marks now lie on the same scale as the SC.
Typical

13. Comparison of Achieved with Typical
Re-scaled HSC in this subject in this school
Achieved
Extract from the re-scaled HSC Biology marks, the marks for the students in this particular school doing Biology. For the sake of making the point, in this example the students taking Biology in this school are shown as vastly superior to a typical group in the analysis (the middle of the green line is considerably above the middle of the blue line).
Typical

14. Achieved Average of re-scaled HSC in this school
Find the average of the HSC Biology re-scaled scores, and then also find………..

15. Comparison of Achieved with Typical
95% probability range of the average
Achieved
…… the uncertainty of measurement of this average, so giving a range within which it is 95% probable that the average lies.
Typical

16. Comparison of Achieved with Typical
Line where achieved exactly equals typical
Achieved
If the achieved result was exactly what was expected, the average for achieved would be exactly equal to the average for expected, and the point representing both would be exactly on the line.
Typical

17. Comparison of Achieved with Typical
However, in this case the achieved result is well above what would have been expected for these students, being shown by the “fuzzy blob” being above the line of expectation. We therefore say that this represents……
Typical

18. Achievement above typical
Achieved
……. Achievement above expectation.

19. Thank you
……….. The end.