Date of Award

Fall 2014

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biological Science

First Advisor

Nancy J. Pelaez

Committee Chair

Nancy J. Pelaez

Committee Member 1

David Eichinger

Committee Member 2

Dennis J. Minchella

Committee Member 3

Jeffery Karpicke

Abstract

Experimental design is an important component of undergraduate biology education as it generates knowledge of biology. This dissertation addresses the challenge undergraduate educators face for assessing knowledge of experimental design in biology by examining knowledge of, and difficulties with, experimental design in the context of first-year undergraduate biology students at Purdue. The first chapter reviews several recent reports that highlight the necessity to increase understanding of the experimental research process as a core scientific ability (for e.g., AAAS, 2011; AAMC-HHMI, 2009; NRC, 2007). Despite its importance, there is limited information about what students actually learn from designing experiments. In the second chapter, the development and validation of a Rubric for Experimental Design (RED) was informed by a literature review and empirical analysis of thousands of undergraduate biology students' responses to three published assessments. The RED is a useful probe for five major areas of experimental design abilities: the variable properties of an experimental subject; the manipulated variables; measurement of outcomes; accounting for variability; and the scope of inference appropriate for experimental findings. The third chapter presents an original 'Neuron Assessment' based on a current research problem related to a disease caused by defective movement of mitochondria in neurons. This assessment provides necessary background information and figures to examine knowledge of experiments through representations and experimental design concepts. A case study method was conducted with oral interviews to investigate interactions among three factors, conceptual knowledge (C), reasoning skills (R) and modes of representation (M). Findings indicate the usefulness of the 'Neuron Assessment' to probe knowledge and difficulties in areas characterized by RED. The fourth chapter examines evidence from the case study participants' written responses to paper and pencil tests to validate the 'Neuron Assessment' as a diagnostic tool for the RED areas. In comparison to the published assessments that formed the basis for development of RED, findings with the 'Neuron Assessment' provide strong evidence for its validity as a probe to distinguish expert and student knowledge from difficulties with experimentation concepts and representations. In summary, a mixed methods approach was used to characterize undergraduate biology students' knowledge and difficulties with experimental design. Findings from this dissertation illuminate knowledge of experimental design at the undergraduate level and open up several new avenues for improved teaching and research on how to evaluate learning about the experimental basis for understanding biological phenomena.

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