Comparing The Impact of a Case Study Approach On Student Learning for
Biology Majors vs. Pre-Nursing Students
Trinity Washington University
125 Michigan Avenue, NE
Washington, DC 20017
(202) 884-9257(office)
deboyc@trinitydc.edu
Cynthia A. DeBoy
ABSTRACT
RESULTS
Case study 1: The Case of the Newborn Nightmare
Question 2: Does The Case of the Newborn Nightmare
improve outcomes for pre-nursing & biology students
for differentiating Streptococcus and Staphylococcus &
associated diseases?
Comparison of assessments from pre-nursing student exams for content taught with and
without case studies
100
100
90
90
80
80
70
70
Percent
Correct
Percent
The Case of the Newborn Nightmare (Wade, 2001) was adapted for both
pre-nursing and biology majors. Through this study, students investigated
the causative agent of a skin disease for which evidence suggested
Staphylococcus. Students worked in groups to create dichotomous keys in
which they identified laboratory tests that would differentiate pathogens
based on distinguishing characteristics. Results for each hypothetical test
were given with which students concluded the disease and causative
microorganism. The assessment tool used for pre-nursing students was
an in-class exam with multiple choice questions, while essay exam
questions were used for upper-level biology majors
Percent
Correct
Percent
Trinity Washington University offers pre-nursing and upper-level
microbiology courses. To elucidate the most effective pedagogy for each
population, assessment data from concepts taught with and without case
studies from each course were compared. The hypothesis was that students
in both courses would score higher on assessments for concepts presented
through a case study compared to concepts taught without one. For both
courses a case study written by Andrea Wade published in the National
Center for Case Study Teaching in Science, University at Buffalo, State
University of NY was adapted. Students investigated the causative agent of a
skin disease for which evidence suggested a staphylococcus infection.
Assessment data indicated that 83% and 75% of 18 pre-nursing students
identified diseases caused by Staphylococcus and Streptococcus,
respectively. In comparison, an average of 79% of pre-nursing students
correctly answered questions for concepts not presented via case studies.
Assessment from biology majors taking upper-level microbiology indicated
that 77 % of 13 students could distinguish the genera and 85% could identify
diseases caused by both genera. In contrast 43% and 23 % of the students
correctly answered questions about pathogenic mechanisms for
Staphylococcus vs. Streptococcus, respectively. In comparison, an average
of 64% of students correctly answered questions on concepts taught without
a case study. Therefore, this case study was effective for teaching biology
majors to differentiate specific genera and to identify the diseases each
causes, but not for teaching mechanisms of pathogenicity. Additionally a
novel case study based on a Shigella outbreak (Mermel et al. 1997) was
developed for the upper level microbiology course as a tool to teach about
gram negative Enterobacteriaceae. All students correctly answered related
assessment questions. In conclusion for this pilot study, assessment
scores for biology majors were improved when using case studies but not
for pre-nursing students.
METHODS
60
50
40
30
20
60
50
40
30
20
0
0
other
A second case study was developed for biology majors based on the 1997
article, “Outbreak of Shigella…” by Mermel et al. A story based on the
article was presented in which students working in a microbiology lab in a
hospital developed gastro-intestinal illness. The objectives were for
students to design laboratory tests to differentiate coliform vs. noncoliform
Enterobacteriaceae, recognize associated illnesses, and develop
prevention strategies. Students worked in groups and based on their
experimental plan, were given “data” for each proposed experiment which
they would analyze to identify the specific genera of Enterobacteriaceae
causing the illness. Groups were given “data” suggesting either
Escherichia coli, Shigella or Salmonella. Each group presented its’
methodology and conclusions to the class.
*
10
10
Case study 2: Outbreak of Shigella
Comparison of assessments from Upper-level biology majors' exams for content taught wit
and without case studies
Case study
In-semester Exam
other
other
Case study
Casestudy
study 1
Case
other
In-semester Exam
Final Exam
a. Pre-nursing
Casestudy
study 1
Case
Final Exam
b. Upper-level biology majors
Figure 2. Percent of students correctly answering questions for concepts
covered by case study 1 vs. other pedagogy assessed with an in-semester
exam and final exam for a. pre-nursing and b. biology students (*denotes
p<.002 for in-semester exam).
Question 3: Does The Outbreak of Shigella case study
improve biology majors’ ability to differentiate coliform
vs. noncoliform Enterobacteriaceae and associated
diseases?
Comparison of assessments from Upper-level biology majors' exams for content taught with
and without case studies
100
References:
90
Assessment methods:
Wade, A.C., 2001, The Case of the Newborn Nightmare. The
National Center for Case Study Teaching in Science, University at
Buffalo, State University of NY
http://sciencecases.lib.buffalo.edu/cs/teaching
Assessment data from an in-class exam and the final exam were used to
compare comprehension of concepts covered in the case studies vs.
concepts that were not. Data from other in-semester exams that did not
assess content from the case study were not included. Average scores
for content covered by other methods of pedagogy vs. each case study
were acquired and standard deviation was calculated. Student’s T test
was applied.
RESULTS
INTRODUCTION
Purpose:
Question 1: What concepts are taught to biology majors
with The Case of the Newborn Nightmare (Wade, 2001)?
Case studies will improve learning outcomes for prenursing and upper level biology majors.
Figure 1. Percent of
students correctly
answering questions
related to
Staphylococcus and
Streptococcus vs.
other topics.
80
70
Correct
PercentPercent
Hypothesis:
100
90
60
50
40
30
20
10
0
Other exam
questions
Staphylococcus &
Pathogenic
Pathogenic
Streptococcus mechanisms
mechanismsfor
identification & Staphylococcus
diseases
& Streptococcus
In-semester Exam
Other
exam
Other
questions
questions
exam
Staphylococcus &
Pathogenic
Pathogenic
Streptococcus mechanisms
mechanismsfor
identification & Staphylococcus
diseases
& Streptococcus
Final Exam
Figure 3. Percent of students
correctly answering questions for
concepts covered by case study 2
vs. other pedagogy assessed with
an in-semester exam and final
exam for biology students.
70
60
50
40
30
20
10
0
other
Case study 2
In-semester Exam
other
Case study 2
Final Exam
CONCLUSIONS
Comparison of concepts enhanced by case studies in upper-level biology course BIOL441
To determine the efficacy of using case studies to teach
differentiation of specific pathogens for pre-nursing and
biology majors
Correct
Percent
Percent
Mermel, L.A., Josephson, S.L., Dempsey, J., Parenteau, S., Perry, C.,
Magill, N., 1997. Outbreak of Shigella sonnei in a clinical microbiology
laboratory. J Clin Microbiol. 35, 3163-5.
80
• The Case of the Newborn Nightmare [Adapted] (Wade, 2001):
• Helped biology students to differentiate Staphylococcus and
Streptococcus and identify associated diseases
• Not helpful for identification of disease mechanisms
• Improved biology majors’ in-semester but not final exam
assessment outcomes
• Did not improve pre-nursing assessment outcomes, perhaps
due to multiple choice vs. essay assessment tools.
• The Outbreak of Shigella case study facilitated biology majors’
distinction between coliform and non-coliform Enterobacteriaceae.
• Pilot data are based on a small sample size but initial conclusions
warrant further investigation.