4 ms·

If you deep dive into demographic groups (https://www.nationsreportcard.gov/reading/nation/groups/?grade=12 https://www.nationsreportcard.gov/reading/nation/gro

If you deep dive into demographic groups (https://www.nationsreportcard.gov/reading/nation/groups/?grade=12 https://www.nationsreportcard.gov/reading/nation/groups/?gra...), you get a bit of a different story, showing a lot of the drop might just be Simpson's Paradox at play and the educational outcomes getting worse for the lower performing students. For instance, non English language learner's reading scores are unchanged over the last 3 decade. It's crashing lower for ELL students. Dive into other metrics and you see the pattern of the lower performing groups performing worse and better performing groups roughly holding.

SamBam 5y ago
Simpson's Paradox isn't really relevant here. All you're describing is the average going down because one group goes down a lot. But that's how averages generally work.
- usaar333 5y ago
  Oh the Simpson's Paradox is that the relative portion of the lower performing groups is increasing as well. For instance, ELL students have increased from 8.1% in 2000 to 9.6% today (https://www.edweek.org/leadership/the-nations-english-learner-population-has-surged-3-things-to-know/2020/02 https://www.edweek.org/leadership/the-nations-english-learne...)
  - onlyrealcuzzo 5y ago
    Simpson's paradox is that several (most, all) groups show an increase, but the average is decreasing. Imagine a simple chart 1980: -----------| students | avg-score poor ...... | 10 ....... | .2 non-poor | 100 ...... | .8 If the chart in 2020 looked like this: -----------| students | avg-score poor ...... | 100 ...... | .25 non-poor | 150 ...... | .85 Both groups increased their average score. But the total average went from (.2x10+.8x100)/110=~.75 to (.25x100+.85x150)/250=~.61
    - danbruc 5y ago
      Which is not actually surprising because the dominant change is the migration from non-poor to poor, not the change of the average score - 1980 has only 9% poor results, 2020 has 40% poor results. When scores change, at first the average scores within groups will change, but if the scores change enough they will eventually cross group boundaries at which point the group averages become more or less irrelevant and the changes are mostly reflected by changes in group sizes. The group averages are bounded by the range of each group and can only indicate if the group is moving towards one of the boundaries, but as scores cross boundaries they start contributing to different group averages and at opposite ends, e.g. decreasing scores will at first contribute at the lower boundary of one group and then at the upper boundary of the next lower group which may increase the average score of both groups, in one case by loosing a low score relative to the group range, in the other case by gaining a high score within the group range.

SamBam 5y ago

Simpson's Paradox isn't really relevant here. All you're describing is the average going down because one group goes down a lot. But that's how averages generally work.

usaar333 5y ago
Oh the Simpson's Paradox is that the relative portion of the lower performing groups is increasing as well. For instance, ELL students have increased from 8.1% in 2000 to 9.6% today (https://www.edweek.org/leadership/the-nations-english-learner-population-has-surged-3-things-to-know/2020/02 https://www.edweek.org/leadership/the-nations-english-learne...)
- onlyrealcuzzo 5y ago
  Simpson's paradox is that several (most, all) groups show an increase, but the average is decreasing. Imagine a simple chart 1980: -----------| students | avg-score poor ...... | 10 ....... | .2 non-poor | 100 ...... | .8 If the chart in 2020 looked like this: -----------| students | avg-score poor ...... | 100 ...... | .25 non-poor | 150 ...... | .85 Both groups increased their average score. But the total average went from (.2x10+.8x100)/110=~.75 to (.25x100+.85x150)/250=~.61
  - danbruc 5y ago
    Which is not actually surprising because the dominant change is the migration from non-poor to poor, not the change of the average score - 1980 has only 9% poor results, 2020 has 40% poor results. When scores change, at first the average scores within groups will change, but if the scores change enough they will eventually cross group boundaries at which point the group averages become more or less irrelevant and the changes are mostly reflected by changes in group sizes. The group averages are bounded by the range of each group and can only indicate if the group is moving towards one of the boundaries, but as scores cross boundaries they start contributing to different group averages and at opposite ends, e.g. decreasing scores will at first contribute at the lower boundary of one group and then at the upper boundary of the next lower group which may increase the average score of both groups, in one case by loosing a low score relative to the group range, in the other case by gaining a high score within the group range.