It's true-- with few exceptions, we encounter students in groups. Student groups are like chemical reactions, where every element present changes and is changed by the other elements encountered.
This is news to almost nobody. Every teacher can tell a story about that one student whose absence would make a usually-difficult class well-behaved. Or maybe the tale of that class where several top students drove each other to greater achievements. Or the student who was an angel one-on-one, but who just couldn't focus when in class.
I've long had a theory that male intelligence is inversely proportional to the number of males in the room. IOW, the more of us you put together, the dumber we act (eg men's softball leagues or Congress). I first developed that theory watching my son's elementary school class proceed from K through 6; the group was infamous because the twenty-seven students included twenty-four boys and three girls.
Value Added formulas, the formulas that promise we can magically and numerically strip away everything not-the-teacher that affects the students-- how can those formulas parse the difference between last year's group of seven year olds who never quite comfortable with each other and this year's group, which tends to give each other the giggles twice a day? How does a magic formula distinguish between the student who is part of a class that functions like a well-oiled machine and the student who dreads seeing her classmates every day?
We don't talk about this much, but one more problem with the reformster agenda is that it takes each student as an isolated unit, a human being with no context. The picture of "individualized" education often portrayed by folks like Knewton (the mad number crunching scientists at Pearson) is that we feed Pat into the Giant Data Bank and the GDB spits out Chris a student that the magic formulas claim is just like Pat. "Here's how Chris learned this stuff," says the magical computer. "Just teach Pat the same way."
This is an odd approach for many reasons, but one of the oddest reasons is that it assumes that Pat and Chris are discrete isolated student units with no real context or social setting.
In reformsterland, people are disconnected and no relationships exist. Teachers and students interact in a Strictly Business manner-- teachers deliver instruction and students respond to it by becoming capable enough to score well on standardized tests. But at least teachers and students interact in some manner; in reformsterland, students do not interact with other students at all. The relationships they form, the culture that they create in their schools-- none of this actually exists. In reformsterland, students travel in isolated bubbles, unaffected by any of the other bubbles around them.
It's ironic, because in reformsterland every one of those bubbles contains an identical data generation unit (formerly known as human children). One size fits them all, and I suppose it doesn't matter which one of the other bubbles is their "friend" because they're all interchangeable, and relationships don't affect anything anyway.
It's just one more way in which reformsterland does not resemble the real world. Because in the real world, students travel in packs, and the packs are interesting and vibrant and affecting because every person brings something unique to the table. And the possible combinations of all these humans are infinite in number, staggering in complexity, and endless in influence, whether reformsters want to recognize their existence or not.