This comment is perfectly representative of what I was talking about. The entire idea that ELL is a “designation for ‘who’s stupid’” is exactly what is untrue, and the limitations of standardized testing propagate this false belief.

ELL is a bucket that has people with learning disabilities mixed with immigrants and children of immigrants. The fact that a 14-year-old Korean kid who just moved to America can’t remember the English word for “photosynthesis” is not a reflection of poor skills in science but poor skills in English. I argue that the intent of a science test is to test knowledge of science, and that giving immigrants poor marks for subjects they are good at is nothing more than a failure of testing. This failure should be known and understood when analyzing test results—no test is perfect, but we should be able to account for known sources of error. Simpson’s paradox is the classic example of what wrong conclusions you can draw when you fail to account for variables which are known to affect the result.