Assessing pre-laboratory work

Discipline Area

Chemistry

Key assessment issue addressed

Using assessment to encourage students in large first-year classes to acquire some knowledge of laboratory exercises prior to attempting the actual practical work.

The initiative

Many students seem to question the hypothesis that it is beneficial for them to learn something about laboratory exercises before attempting them for the first time. As a long-standing "goose", I have tried many approaches to encourage students to do some preparation for their laboratory work. Most have involved the allocation of a few marks as an incentive. Some spectacular failures are outlined below and a 'better way' is proposed for 2002.

The first initiative was ineffective because although it was good for the students ("ganders"), it was impractical for the staff ("geese") to implement effectively. Due to increasing incidences of last-minute 'copying' of pre-lab exercises (a practice which does NOT lead to deep understanding or reflection), for Session 1, 2001 I wrote a set of more reflective pre-lab questions which were to be assessed VERBALLY during each laboratory class. This was consistent with our effective teaching strategy of 'questioning students'. However, there was mutiny among the tutors. It was impossible for us to have a detailed discussion with each of the 12-15 students in our groups; in a lab, the priority is always (unavoidably) supervision of the practical work. We reverted to 'handing-in-before-the-lab-and-getting-feedback-next-week'. Although the new questions had been ideal for discussion, they were not very effective for this conventional mode of marking. Another strategy was needed.

The second strategy was less than ideal because, although it suited the "geese", it did not promote effective learning among many of the "gander". Sensing they had me on the run, my long-suffering tutors suggested an unseen quiz for Session 2, arguing that (a) it was effective in other first-year subjects (why did I ever listen to THAT argument?) and (b) it would be fairer for students by rewarding hard work. The tutors liked the new system because lateness to labs was eliminated, students' results closely matched their preparation efforts, and less time was needed for the pre-laboratory talk (because some of the points had been covered in the quiz). At a focus-group interview of (self-selected, motivated) students, about half the group admitted that the quiz encouraged more thorough preparation; but the others felt they had no guidelines as to the important or relevant concepts. The external (off-campus) students all disliked the unseen quiz and many performed badly. One of the tutors said to me in alarm "this approach does not work for these students!"

After consultation with staff and students, in 2002 I will provide (in the lab manual and on the Subject web-site) a set of 6-8 pre-lab quiz questions; some on detailed technical points, some on background theory and some, requiring reflection, on broader concepts. At the beginning of each lab session, there will be a timed quiz using 2 or 3 of these questions. This process will give students the guidance they seek, be seen to be a 'fair' test and also eliminate cross-class plagiarism because different questions from the set can be used for different lab sessions.

The reason for the initiative's effectiveness

The new approach is based on student and staff evaluation of ineffective past practices, and will hopefully be good for both the "goose" (with tutors perceiving a fair test of student conscientiousness) and the "gander" (with students having guidance for their laboratory preparation).

Further details

Deidre Tronson, Lecturer in Chemistry
School of Science, Food and Horticulture
Hawkesbury Campus (Bldng K12)
University of Western Sydney
Ph: 02 4570 1634
d.tronson@uws.edu.au