1. What changed?
When California reports test scores, it splits students into two groups: students facing financial hardship (for example, their family qualifies for free or reduced-price school meals) and students not facing hardship.
In San Mateo-Foster City, the number of students counted as facing hardship went up a lot in just three years.
Out of every 20 students tested in grades 3–8. "2023" means the spring 2023 test (the 2022–23 school year), and so on.
2. Is that normal?
No. In most California districts, this number barely moved. Out of about 580 districts, only 19 had a bigger jump than San Mateo-Foster City.
Some nearby districts did see a big jump in 2024, but it went right back down the next year. In San Mateo-Foster City, it stayed up and then went up again.
| Out of 100 students, how many were counted as facing hardship? | 2023 | 2024 | 2025 | 2026 |
|---|---|---|---|---|
| Hillsborough | 2 | 20 | 3 | 2 |
| Portola Valley | 6 | 25 | 4 | 5 |
| San Carlos | 10 | 21 | 11 | 11 |
| San Mateo-Foster City | 31 | 42 | 40 | 45 |
3. Why does it matter? The "Will Rogers effect"
Moving students from one group to the other can make both groups' scores go up, even if no student does any better. Here's a made-up example with six students.
Before
After moving one student
4. How this could have happened in San Mateo-Foster City
The district's report says both groups of students improved from 2023 to 2026. That's true. But over the same time, about 1,100 students left the "not facing hardship" group and about 700 more joined the "facing hardship" group. And the score for all students together went down.
Percent of students who met or exceeded the reading standard. Math looks similar: both groups went up while all students together stayed about flat (51% to 50.5%).
This is exactly the pattern in the made-up example. If the students who switched groups scored somewhere in the middle (below most "not facing hardship" students but above most "facing hardship" students), moving them would push both groups' scores up on its own.
It's also rare. Across California, only about 15 districts had both groups go up while the overall score went down. San Mateo-Foster City is one of just four where it happened in both reading and math, and it had the biggest drop in overall reading scores.
5. What this means
What it does not mean
- It doesn't prove anyone did anything wrong.
- It doesn't prove the gains for each group are fake. Some real improvement could be mixed in.
What it does mean
- "Both groups improved" isn't enough, on its own, to show students are doing better.
- The all-students score is the most reliable number, and it went down.
- It leaves a fair question for the district (below).
Why are so many more students now counted as facing hardship?
Sources & notes
Data: California Department of Education CAASPP research files for every California district, 2014–15 through 2025–26 (grades 3–8 combined). "Facing hardship" is CDE's "socioeconomically disadvantaged" student group. District rankings include about 580 districts with at least 300 tested students, not counting county offices of education. Numbers on this page are rounded to keep them simple.
For every year, school, grade and student group, see the interactive CAASPP dashboard.