Class Test 4, 2013

Well, this was a train smash.

Overall score, excluding the no shows = 70%, in line with what happened in the first class test what seems a life time ago, but down about 10% from the previous two class tests (2, 3). Thus, the steady upward march of (measurable) learning progress gone, just like that.
I struggle to understand why. The good news, and it really is good news, is that the half of the test which dealt with critical analysis of the science behind a media report was well handled. I guess that sort of critical thinking is one of the most important things the students can carry forward from this class.


But the bad news was that the part of the test which probes comprehension of what I say in class was really poorly handled. When I look hard at the questions, I realize what I have done is write questions that really required the students to be in class and listening. The answers to the questions the students did most poorly on aren’t on the handouts or the slides. For instance, Barry Marshall, who got the Nobel Prize for discovering that H. pylori causes stomach ulcers, drank the bacteria in a desperate attempt to prove his theory. I discussed this in class: what does a sample size of one tell you anyway? Is it ethical? And critically for the question I asked, he got sick, but did not get a stomach ulcer. So his own data point is evidence against his hypothesis. It took large randomized trials to provide convincing evidence for the hypothesis. Barry Marshall drinking the bacteria was at best an anecdote – and one which argued against the hypothesis. Apparently only a third of students took that message on board.
By chance, I took attendance the day I talked about Barry Marshall – only 60% of the class was present. So that probably explains why 40% of the students did not know the answer. Why did half of those that were there get the wrong message? Was it because they were not paying attention? Or because I did not explain it well enough?
The other odd thing about that particular question is that a few minutes on Wiki with a critical appreciation of the hypothesis under test would have enabled anyone to work it out. I thought I had been banging on so hard determining what the hypothesis is, what was actually measured, and how that matched the hypothesis. Maybe I need to bang on more. 
The grade distribution break down: A, 2; A-, 4; B+, 9; B, 7, B-, 19; C+, 12; C, 30; D, 35; Fail, 29 + 17 no shows.
I wonder if I should have been more ruthless probing comprehension of class material in previous tests. So much non-attendance…and in class, so much inattention. Its hard not to get cynical. Saying over and over again: come to class and listen. This course is brutal on non-attenders. Is the only way to get the message across to put in more probing questions early in the semester?
One of the interesting things about blogging about a course is that you get to see what you were thinking about at the same time in previous years. I see in both 2012 and in 2011 I had the same worries. Performance on Class Test 4, 2011 was as disappointing as this. I see was then agonizing about the same things, beating myself up the same way. 
There must be some lesson to draw from that.

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