Creating a reliable instrument to assess students’ conceptions of studying biology at tertiary level

As part of a study to assess the impact on tertiary biology students of changes to the NSW HSC biology curriculum, we developed a questionnaire to survey student conceptions of biology. This required the creation of multiple Likert-scale items in two sub-scales: (i) fragmented conception of biology (e.g., Biology is just the study of facts); and (ii) cohesive conception of biology (e.g., Biology allows predictions to be made about everyday life and situations). Before implementing the questionnaire to address our main research questions, and because this was the first time, to our knowledge, that a Conceptions of Biology Questionnaire had been designed, we needed to validate its use in distinguishing between students who have different conceptions of biology as a science discipline. We used data from students, collected in their first week of tertiary biology, to analyse the reliability of the Conceptions of Biology items. Analysis using SPSS software indicated that items in the two conceptions sub-scales were individually reliable (Cronbach μ values > 0.6). However, factor analysis indicated that items in the fragmented sub-scale were not being discriminated from items for cohesive sub-scale by students. This result allowed us to reword the fragmented conception items before re-administering the questionnaires and thus demonstrate improvement in students’ ability to discriminate between fragmented and cohesive statements. We are now confident that the questionnaire will accurately discriminate between students with different conceptions of biology and recommend this practice for all future such investigations.