[fnordpiglet]

I’d note it’s not the mean but the median here. But the IQ is a good example where 100 is defined as the median but has had to be revised upward over time as test performance improves overall. So, in this case they set a fixed definition of grade level being slightly above the median at the outset of the measurements (presumably to induce HN headlines that attract clicks and ultimately funding for schools because more than half are under “grade level”) then over time the goal is to improve on the initial score. In 2019 and 2018 it’s interesting to note the score breached 50% for the first time, peaking at 51%. It’s slipped but presumably that’s a “large scale event” effect and will mean revert to the 2019 levels and continue advancing with time.

But even with the great results in 2019 you can still say “49% of California students are less than grade level” and it looks really bad and people post about how bad public schooling is and hand wringing ensues. - again ultimately leading to more funding, when in fact it’s a real milestone achievement to have lifted such a huge number of students so far in so short a time.

It’s always fascinating to watch the click bait statistic name induce reliable and predictable behavior every time, even when the actual data tells the exact opposite story. Very clever whoever decided to make “grade level” greater than the median performance.