Standardised tests and Differentiation?

I recently came across the figure above on one of my social media apps and thought that it served more of an answer than 280 characters. Here’s what I wanted to respond:

Standardised tests and differentiation. Think about it and try to let science, logic and reasoning prevail over gut feelings and philosophy.
Differentiation should be convergent. That is, all students should be helped to achieve a similar, preferably the same, but in any event minimal level of knowledge and skill for all. For convergent differentiation, we differentiate the instructional approach or strategy (what we call didactics in the Netherlands and what Americans and Brits call pedagogy). In divergent differentiation, in contrast, we differentiate the goals such that the goals are higher for better students (define that as you may: cognitive, social-economic, …) and lower for poorer, struggling and disadvantaged students. You can only see if you’ve achieved this goal of bringing everyone to this similar, same, or minimal level if everyone receives the same – standardised – test[1].
Finally, if you use divergent differentiation, everyone learns something else and you increase the knowledge gap (the Matthew Effect; the better/more edvantaged student learns more and the poorer/disdvantaged students learns less) and disadvantage the already disadvantaged! It’s just that simple.

[1] Note: I’m not saying that all standardised tests are good (i.e., they reliable, valid, fair). What I’m saying is that they’ve been calibrated, and hopefully are valid, reliable, and fair.