Placement testing is tough. Doing it well can be time consuming and resource intensive, and doing it with insufficient rigor can lead to “slippery” leveling, where, say, a level 3 one year is different in ability from a level 3 in future years.
I don’t have any all-encompassing answers to this problem, but in using a popular computer-adaptive test for placement purposes, I’ve begun to recognize a few broad categories that students can be broken into, according to the grammatical complexity of their utterances.
Level 1 – This level is marked by strings of simple sentences. Use of and may occur as well. Before you assume that a student is at this level, make sure you’re asking questions that call for more complex answers. Ask plenty of elaboration questions like why and tell me more. If students still answer in simple sentences, score them a level 1.
Level 2 – At the second level, students begin using more challenging coordinators like or and but, as well as subordinates like when, so, if, and because. The most common one you’ll hear is because, but double check that students are actually using the word correctly. Many students seem to use it as an all-purpose connector.
Level 3 – You have to listen closely to recognize this third level. It’s marked by relative clauses and noun clauses. Most often you’re listening for that and which introducing clauses that describe nouns, as in the house that I live in and my job, which I love. Also in this category are noun clauses, as in I made the decision that we would move to Texas.
Ask questions of increasing complexity to get a sense of what students are capable of. I generally find that students reach a pretty hard stop between each of these levels. That is, students are either using level 2 language constantly or not at all. The same levels, of course, could be found in student writing.