Understanding the HSC Moderation, Adjustment, and ATAR Scaling Process

The journey to your HSC and ATAR can be complex, with various stages of moderation, alignment, and scaling that ensure fair assessments across different schools, years, and subjects. In this post, we’ll break down how each component works and how your final ATAR is calculated.

1. HSC Results: What They Are and How They’re Formed

Your HSC results come from two sources: the examination mark and the assessment mark:

• Examination Mark (50%): This is your mark from the actual HSC exams, often called "externals." It counts for 50% of your final HSC mark.
• Assessment Mark (50%): This represents your internal school assessments, often referred to as "internals."

These two components are averaged to get your HSC mark, which is then used for ATAR calculation.

2. Who Handles the ATAR?

The ATAR is calculated by the University Admission Centre (UAC), not NESA (the body responsible for HSC exams). UAC takes your HSC marks, scales them according to subject difficulty, and ranks them against the rest of your NSW/ACT cohort (including those who have dropped out since Year 7) to create your ATAR.

3. Alignment: Fairness Across Different Exam Years

Each year, the HSC exam can vary in difficulty. To account for this, an alignment process adjusts your raw exam mark to an aligned exam mark. This way, students who happened to sit the exam on a harder year are not penalised unfairly. Aligned marks help set performance standards across years.

Simply put, the harder an exam is on a given year, the more generously your raw exam mark will be aligned upwards.

To get an idea of what the aligned marks look like, you can take a look at the raw marks database, which is a public repository containing examples of past conversions.

4. Moderation: Fairness Across Different Schools

Schools across NSW set different exams and mark differently. To ensure fair comparison between the assessments issued by different schools, there is a moderation process, which adjusts your internal assessment marks based on the difficulty and harshness of your school's internal assessments. This is done so based on a given school's students' performance in the HSC exams.

For instance, if a school’s students perform well in a subject's HSC exam, internal assessment marks are moderated upwards.

This ensures students with harsher internal marking standards aren’t unfairly penalised.

Example: Imagine students Ashley, Bob, Cathy, Dennis, and Eric with the following internal ranks and HSC exam results:

The moderation process ensures that the moderated school marks have the same mean as the students' aligned exam marks. In this process:

• NESA ensures that the top moderated school mark matches the top aligned exam mark achieved by the students from that school
• NESA usually does the same for the bottom moderated school mark, but this isn't always the case
• Students in between the top and bottom school marks receive a moderated school mark that's roughly proportional to the gap in their original school marks

5. Scaling: Fairness Across Different Subjects

Subjects can vary in difficulty, so the scaling process adjusts marks based on the comparative challenge of each subject. For example, harder subjects like Mathematics Extension 2 tend to scale up.

To do so, scaling considers how students in each subject perform in common areas (such as English) to determine the relative difficulty of each subject.

In essence, scaling ensures that students aren’t disadvantaged or advantaged by their subject choice. You can check specific scaling for your subjects through HSC scaling reports from previous years to get an idea of how your subject choice may impact your ATAR.

6. The Final ATAR: Ranking Across the State

Your ATAR is calculated by summing scaled marks from your best 10 units, including at least 2 units of English. This total mark out of 500 is then compared with others in your cohort (everyone in NSW/ACT who started Year 7 at the same time that you did). Your ATAR reflects your standing as a percentile rank, rather than as a simple mark.

For example, an ATAR of 99.30 indicates that you lie in the top 0.70% of the cohort.

7. Key Takeaways: How to Maximise Your ATAR

By understanding these processes, you gain insight into how your efforts throughout high school contribute to your final ATAR. It’s designed to create a fair system that accurately reflects the achievement and abilities of all students across NSW, balancing school assessments, HSC exams, and subject challenges.

Here are some key tips you can take away:

1. Alignment: The HSC being more difficult on the year you sat it will not affect your final HSC mark adversely.
2. Moderation: It's in your best interest to have the highest school mark and rank possible, but it's also strategically important to support your peers in the final HSC exam (especially those with lower school marks). Unless you are ranking 1st at your school, a lower school average mark in the HSC exam may result in your school assessments being deemed easier, and your moderated exam mark decreasing.
3. Scaling: Chemistry, Physics, and Mathematics Extension 1 and 2 are some of the highest scaling subjects, as they are deemed to be more difficult. Ultimately, however, you should pick your subjects to your best strengths, as a low mark in a better scaling subject may be worse than a high mark in a more poorly scaled subject.

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Chemistry, Physics, and Mathematics Extension 1 and 2 are some of the most popular subjects selected by top students, because of the better scaling that comes with their difficulty.

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