[sokoloff]

I don't have much doubt that this will increase educational inequality and it being only 8% of compulsory education might understate things, given the "stacking" nature of each year building on the foundations set in prior years.

If you miss learning addition well, subtraction and multiplication is going to be hard. If you can't subtract and multiply, then learning division is going to be hard. If you can't multiply and divide, algebra will be impossible, but many life tasks will also be more difficult.

[edmundsauto]

Isn't it possible that it's the elite students who will be hurt the most? Suppose they are getting 100% value from education. If a less privileged student is only getting 20% value from education, a 10% relative decrease only makes them 2% worse off.

My point is not that this is the right interpretation, it's just that I don't think it's settled about how much it will impact students, and which groups will be impacted disproportionately. Points about nutrition, getting out of abusive homes, etc., are all interesting and relevant and outside the scope of what I mean, which is purely focused on education outcomes.

[sokoloff]

Elite students from lower socioeconomic strata will likely be harmed. Elite students from upper strata will probably pull farther away (though may or may not suffer as compared to the counterfactual non-pandemic case).

To use your model, what you say is possible, but I think it's equally possible that the delta is additive rather than multiplicative. A 20% student and a 100% student might both lose 10% or 20% to [10%, 90%] or [0%, 80%] without intervention by involved parents.

My kids (grade 4 and 6) are getting a ton of dedicated 1:1 time including more coding time, paid math programs they enjoy playing, white-boarding problems with us, watching Nova/Nasa/other science content with us, and a lot more reading than if they were chained to a desk learning 2 hours of material in 6.5 hours. They might do better in this half school, half home school situation.