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Steve Barclay: How Do You Teach Experimental Design and Literature Analysis to a Class of 100 Seniors (with no TA)?

Bact 526 (Microbial Physiology) is required of all seniors majoring in Bacteriology. A few seniors in Genetics, Biochemistry, and Medical Microbiology, as well as, first year graduate students in several departments also register. The students are generally well-prepared, having had two courses in genetics and one in biochemistry, if they are UW seniors. Typically, 100 students are in the class.

My problem has been to find a teaching style and a form of examination appropriate for a large class of students who will be graduate students or employees in less than a year. I want them (1) to become familiar with current areas of research in microbial physiology, (2) to know several general strategies commonly used to analyze problems in this area, and (3) to begin reading current literature critically.

The problem before me seemed to be finding a way to teach the language, microbial physiology. Students need to know both the vocabulary and grammar (or structure) of microbial physiology. They need to know the details of microbial physiology necessary for them to join the conversation and participate as young professionals. They also need to understand the logical structure (grammar) of the field to analyze current problems and to identify new opportunities.

After teaching the course once in the format of standard lectures and short answer/essay exams, I adopted the method of giving standard lectures (two power lectures each week) and take-home exams. Two of the first lectures show the students how several commonly used genetic and biochemical methods can be used sequentially or in parallel to analyze current problems. These techniques come up repeatedly through out the course as we cover recent research. The remaining lectures are standard information transfer and cover topics of current interest that are unresolved. The take-home exams attempted to duplicate a graduate seminar course. That is, students were given a paper to read in detail. They were asked to answer questions regarding the overall strategy used by the authors, whether the authors really measured what they claimed to measure and why the authors used various methods. They also had to comment whether there is a better way to tackle the problem and suggest new experiments to analyze the problem in more detail. Other questions asked for extended essays to summarize a body of ideas covered by the lectures. Still other questions were smaller problem sets asking them to use any of several methods appropriate for solving the problem, which was either artificial or taken from the literature.

Not wanting to police the students to be sure that their efforts were independent, I told them they could work with each other to complete the exam. The only requirements being that they list with whom they worked on the first page (i.e., give credit for sources of their ideas) and they write the exam in their own words (no secretary for the group who writes a common answer to one or all the questions). I graded the exams without the help of a T.A. This took many hours (40-50 hrs).

The students were enthusiastic about the overall approach. They felt they learned more by discussing the exam with peers and did a great deal of teaching of each other. Because most of the students work in labs and have knowledge of different techniques, working together allowed them to learn new methods and to assemble them into strategies that were appropriate. Take-home exams were new to the students. All found them more difficult than in-class exams (or more time consuming than studying for an in-class exam), but more interesting because they were dealing with current research problems. Some students commented that they had learned many of the techniques in genetics and biochemistry courses, but they had not realized how to apply them sequentially to solve a problem. Most students wanted the lectures to remain as they were, straight information transfer.

I enjoyed grading the exams (somewhat) because some answers had more insight or novelty than I expected. The answers were uniformly more thoughtful. Also, grading was easier because students working together in a group gave similar answers.. A T.A. could make the grading much easier. However, the T.A. ought to be rather advanced because some answers were quite novel and interesting. I wondered whether there were free-loaders who were getting a better grade than they deserved as a result of working in a group. Therefore, the final was given during the final exam period as a standard short essay exam in two hours. No student scored dramatically lower on the final. In summary, the students were conscientious and benefited by having take-home exams.

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UW-Madison, October 1998