There are plenty of very long-term studies going on where groups are identified and then followed over years or decades.
Another approach is today you might go looking for people with different levels of airborne lead exposure as a child, and then compare the average income today to see if their is correlation etc. In these kinds of studies the treatment groups weren't wittingly part of the experiment, but you can look backwards.
Either way, in 20 years we'll probably be able to identify schools where AI texts predominated earlier than other schools and, adjusting for other factors, try and tease out the actual impact of that choice.
I mean the thing is, ethically speaking, there is a strong supposition that the AI predominating instructional format will underperform the other formats, therefore you are essentially putting large groups of people, on purpose, in learning situations the theory is will underperform for the rest of their lives.
That seems like a bad thing.
I suppose that it will happen however, and the backwards looking thing will be what is done to determine the result.
