Here’s a mildly interesting article about student responses to speaking question three. The authors have charted out the structure of two sample questions provided by ETS, and tracked how many of the main ideas students of various levels included in their answers (again, provided by ETS).
There is some good stuff in here for TOEFL teachers. Particularly in how the authors map out the progression of “idea units” in the source materials. They identified how test-takers of various levels represented these ideas units in their answers, particularly how many of these idea units they included in their answers. Fluent speakers (or, I guess, proficient test-takers) represented more of the idea units, but also presented them in about the same order as in the sources.
Something I found quite striking, is that one of the question sets studied was much easier than the other one, something described by the authors of the report. I am left wondering how ETS deals with this sort of thing. The rubric doesn’t really have room to adjust for question difficulty changing week by week.
There is also a podcast interview with one of the authors.