Interpreting SEA composite scores

The SEA placement process using Composite scores to assign students into schools. But many parents don't know how to interpret the SEA "composite score." This post is here to help.

The composite score represents the student raw marks as compared to the performance of all other children who wrote the exam that year.

To expand on that:

Every year about 17,000 students write the SEA Exam. Some of them will do very well, some will do less well. You can find the average mark among those 18,000 students called the "mean", which is just the average mark. The mean mark for each subject is printed on the SEA results sheet, but is also announced by the minister and published in the papers. The mean varies every year with each group of test-takers.

A composite score of 200 is a performance right at the mean.

For example, if the mean mark for this year is 54.3%, and a student got 54.3%, his composite will be right at 200.

If the student mark is higher than the mean mark, the composite will be above 200.

If the student mark is lower than the mean mark, the composite will be below 200.

This is mathematical truth. I detail the calculation in a separate blog post (click here).

A composite of 230 is one standard-deviation above the mean.

The standard deviation is a measure of how much the marks are spread out. The standard deviation is usually around 22% or 23% or 24% or somewhere thereabouts. It varies year-to-year.

Example: if in a given year the mean is 54.3% and the standard deviation is 23.1%, a composite of 230 would be 54.3% + 23% = 77.4%.

A composite of 260 is two standard-deviations above the mean.

However, this may not be mathematically possible in most years.

In 2022, the mean mark was 43% with a standard deviation around 23%. A composite of 260 required only about 89% (in 2022), which a couple students got.

The mean mark in 2025 was 57%, with a standard deviation of around 23%. A student would therefore need to get 103% on the exam to get a composite of 260. But the exam is limited to 100% (all correct), so nobody got a composite of 260 in 2025.

Composite score variation Year-to-Year.

Note: The mean and standard deviation change every year with every group of test takers. For that reason, even the same exact raw marks would generate a different composite score year to year.

Consider the covid years - 2021 and particularly 2022. Those years the average student performance was bad. In 2022 there was a mean mark of 43%, well below normal.

But if you were looking at the composite scores, you might think the opposite -- the composite scores cut-off scores in 2022 generally were much higher especially for the first-choice choice schools.

Why? It is NOT that the top students did better in 2022.. they didn't.. actually the opposite. Only 89 students got over 90%, but that any high mark was much above the average.

In 2025, the top students did much better (421 students scored over 90%), but the composite scores cut-off scores were much lower. Why? Because the mean mark was much higher.

Remember the composite is the student marks relative to the mean. If the mean is 43%, the composite can run up really high. If the mean is 57%, there is less room for the composite to run up.

Now that we are firmly in the post-pandemic period, I expect future exams to be closer to 2023, 2024 or 2025 results, or even the pre-pandemic period (2017 or 2018 cut-offs).

If you are using the pandemic-era cut-off sheets (2021 or 2022), note those are very distorted due to the large learning gap those years. I would recommend not using 2021 or 2022 cut-offs.

The latest we have at the time of the blog post is 2023 cut-offs, which I have retyped as a spreadsheet and listed the approximate percentages here. You can sort by Ascending or Descending in your spreadsheet program (Excel, etc)

2023 SEA Cut-offs with Percentages (Excel file)

Explicitly: Do not compare the composite score for a student in SEA 2026 to the composite score cut-off a school had in SEA 2024 or SEA 2023. Cut-off scores vary year-to-year.

Remember the cut-off scores are descriptive, not prescriptive. No student is compared to a pre-determined cut-off score. The cut-off score only describes the score of the last child placed in the school on merit.

Watch the video on SEA Placement if you haven’t already:

https://www.facebook.com/CNC3Television/videos/2967476716655757/