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HOW WE TEACH
Department of Physiology, University of Kentucky College of Medicine, Lexington, Kentucky 40536
Abstract
The aim of the present study was to determine whether a significant relationship exists between a student’s college (Allied Health, Arts and Science, Education, and Graduate School) and achievement in an advanced-level course in human physiology (PGY 412G). The mean percentage of correct answers on four multiple-choice tests, collectively totaling 400 points, was used to assess each student’s performance. A four (college)-by-three (academic year) analysis of variance was used for statistical comparisons among 660 students enrolled in PGY 412G from the fall semester of 1995 through the spring semester of 1998. Subsequent pairwise comparisons tests found that the College of Education students had a significantly lower mean percentage of correct answers (61%) compared with students in each of the other colleges (P < 0.001). No significant differences in percentage scores were found among students enrolled in Allied Health (78%), Arts and Science (78%), or the Graduate School (77%). Also, percentages of correct answers averaged across all students were significantly lower during the 1997–1998 academic year than those in either the 1996–1997 year (P < 0.001) or the 1995–1996 year (P < 0.05). Students’ scores during these two earlier years did not differ significantly. Upward letter grade adjustments based on class distributions were made each semester, and more As and Bs and fewer Cs and Ds were given as course grades than expected from an absolute assessment scale. This grade inflation benefited low-scoring students from all colleges, particularly those students enrolled in the College of Education. To improve the understanding of human function of these low-scoring students may require special educational programs.
Key words: science education; colleges and academic performance; grade inflation
Many educators and scientists are concerned with college graduates’ comprehension of scientific principles and concepts (1, 4, 10). Because of these perceived deficits, widespread support exists for improving science education at both precollege and college levels in the United States, and numerous innovative proposals have been advanced (2, 5, 11, 13). Research suggests that a common educational solution adaptable to all students is unlikely and that different solutions will be necessary depending on the age, background, and gender of the students (8, 9, 13). Yet, little quantifiable information exists on the academic performance in science-oriented courses of students enrolled in different divisions (colleges and graduate programs) of a university.
Most advanced-level courses in general human physiology try to provide a rigorous introduction to scientific principles and concepts; consequently, performance in such a course may be a useful indicator of the general level of science knowledge of students majoring in different disciplines. Therefore, the primary aim of the present study was to determine whether a significant relationship exists between a student’s college and achievement in an advanced-level course in human physiology. A secondary aim was to evaluate whether significant grade inflation occurred in this course. There were 701 students enrolled in a Principles of Human Physiology course (PGY 412G) at the University of Kentucky through the three academic years of this study. Over 94% of these students were from three colleges (Allied Health, Arts and Science, Education) and the Graduate School, and they served as the study population (n = 660).
METHODS
Course description and instructors.
Principles of Human Physiology (PGY 412G) is a four-hour credit course offered during both fall and spring semesters at the University of Kentucky for students of the allied health professions and any other students interested in an in-depth exposure to physiology. The listed prerequisite for PGY 412G is Elementary Physiology (PGY 206) at the University of Kentucky or an equivalent course taken elsewhere. The course consists of four didactic lectures every week with no laboratory component and with an average semester enrollment of about 110 students. The general purpose of the lectures is to reinforce and expand on the material presented in the course textbook rather than to simply review textbook information. The most recent editions of Vander, Sherman, and Luciano, Human Physiology: The Mechanisms of Body Function (14) were used as basic textbooks during the six consecutive semesters (fall, spring) across the three academic years (1995–1996 through 1997–1998). During the study period, PGY 412G was team taught with five faculty members each semester. Although most of these instructors presented lectures in the areas of their research interest, lectures focused on basic concepts and problem-solving skills rather than on the presentation and memorization of specific research findings.
Study population.
The total student population across the three-year study period and their respective colleges/school are presented in Table 1. As may be seen, students in three colleges (Allied Health, Arts and Science, Education) and those in the Graduate School constituted 94% of the total class enrollment of 701 students. Consequently, only this selected sample (660 students) was used for statistical comparisons between a student’s college/school and PGY 412G test performance. In this selected sample, over 96% of the students in the College of Allied Health were pre-majors or majors in physician assistant studies (43%) or physical therapy (54%). In the College of Education, over 99% of the students were majoring in kinesiology (64%) or physical education (35%). In the College of Arts and Science, 70% of the students were majoring in biology, with majors in combined topics (10.2%), chemistry (5.9%), and undeclared or nondegree programs (7.5%) increasing the total to over 90%. A much more diverse group of students was enrolled in the Graduate School, with 16.2% of the students postbaccalaureate (no degree program) and the four highest percentages of majors in biomedical engineering (28.3%), kinesiology and health promotion (16.2%), clinical nutrition (12.2%), and home economics, nutrition, and food science (9.1%). The remaining students enrolled in the Graduate School (18%) were spread across another 10 majors. For convenience in presentation, the Graduate School will be classified as a college in the remainder of this article.
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In the course syllabus, students were informed that course letter grades would be assigned from an absolute measurement scale of A (90 to 100% of correct answers), B (80 to 89%), C (70 to 79%), D (60 to 69%), and E (59% and below). Students were guaranteed these letter grades if they achieved the corresponding percentages (i.e., for 90% or higher a letter grade of A was guaranteed). However, in every semester, final course grades were assigned using upward letter grade adjustments based on class distributions.
The relation between semester performance (fall or spring) and academic year for students from the four colleges could not be meaningfully evaluated because of the small numbers of students enrolled from some colleges during a given semester. As examples, in every one of the six semesters, at least one college had an enrollment of only five to nine students. Therefore, a two-factor, between-subject analysis of variance (ANOVA) was used for statistical comparisons, with college and academic year as the two factors. In this ANOVA, the lowest number of students enrolled from a given college in any academic year was 27. Significant effects in this overall ANOVA were subsequently analyzed by post hoc pairwise comparisons using the Tukey-Kramer test for unequal sample numbers (15).
RESULTS
For students in the four colleges, the mean percentages of correct answers in the course (absolute measurement scale) for the three academic years are presented in Fig. 1. The four (college)-by-three (academic year) between-subject ANOVA indicated that the two-way interaction of college by academic year was not significant, F (6,648) = 1.46, Fig. 1; however, both the main effect of college, F (3,648) = 91.15, P < 0.000001 (see Fig. 2), and the main effect of academic year, F (2,648) = 6.35, P < 0.001 (see Fig. 3), were significant. For the significant college effect (i.e., comparing mean college scores averaged across all three academic years, Fig. 2) Tukey-Kramer pairwise comparisons indicated that students enrolled in the College of Education had a significantly lower mean percentage of correct answers compared with the test scores of students in each of the other three colleges (P < 0.001). Across this same three-year period, no significant differences among students in the other three colleges were observed. The mean course scores for students in these three colleges were consistently above 77% of correct answers for each academic year, and the mean course scores for students enrolled in the College of Education were always below 62% of correct answers (Fig. 1). This yearly percentage disparity in course performance represents a consistent difference of over 60 points in the cumulative total of 400 points for the four semester tests.
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Many factors could explain this slight, but statistically significant, decrease in test scores during the 1997–1998 academic year. Post hoc examination of the data indicated that an increase in the difficulty of the neurophysiology examination during this last year appeared to a major factor in the overall decline in course performance. Consequently, two separate post hoc ANOVAs across the three academic years were done on students’ performance on the first neurophysiology examination and on the average of the subsequent three examinations. Different combinations of major physiology sections were tested in subsequent examinations during the three-year study; consequently, because of this confounding, an average measure was necessary for the last three examinations (see METHODS). For both analyses, like the main ANOVA, the interaction of college by academic year was not significant, and the college effect was significant (P < 0.0001). But a significant effect of academic year was found only for the neurophysiology examination (P < 0.0001) and represented a decline to 62% correct answers during the 1997–1998 academic year from the 75 and 74% correct answers during the previous two academic years. Across the three academic years, the range of test scores for the other examinations was 74–75% correct answers.
As indicated in METHODS, upward adjustments in course letter grades were made each semester. In Table 2 are comparisons among the expected letter grades guaranteed from the absolute percentage scale described in the course syllabus and the actual course grades received by students in the four colleges. More As and Bs and fewer Ds and Es were given as course grades than were expected from the absolute percentage scale. Indeed, with the guaranteed grading scale, 26.8% of the total student population should have expected a letter grade of D or below, but only 8.8% of students actually received course grades below a C. This upward grade adjustment benefited low-scoring students from all colleges, particularly those students enrolled in the College of Education. In this college, 80% of enrolled students should have expected course grades below a C, but only 35% of the students received course grades of Ds or Es (Table 2).
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A significant relation did exist between a student’s college and the student’s achievement in an advanced-level course in human physiology (PGY 412G). Across the three academic years of the study, students in the College of Education had significantly lower test performance than students enrolled in the other three comparison colleges. For these academic years, students enrolled in the other three colleges did not differ significantly among themselves (see Fig. 1).
Although limited biological backgrounds for students enrolled in the College of Education might have contributed to their low course scores, the evidence for such a possible association is still debatable. For example, Rovick et al. (7) have presented suggestive evidence that prerequisite biological knowledge may not be necessary for students to master advanced physiological content. Similarly, Richardson (6) found that completion of a prior elementary physiology course by students at the University of Kentucky (PGY 206) or by students in another academic program did not improve their learning of advanced cardiovascular material in PGY 412G. In an extensive study of predictive factors, McCleary et al. (3) have reported that prior college grade point average (GPA) and the number of college science courses taken by students prior to enrollment were significant predictors of success in an undergraduate physiology course. An interaction between these two predictors was observed as the likelihood of passing undergraduate physiology increased with the number of science courses taken for students with a GPA greater than 3.0, but it decreased for those students with a prior GPA less than 3.0 (3). It is not surprising that prior GPA would be strongly associated with passing an elementary physiology course, as past academic success is a good predictor of future academic success. The reported interaction, however, suggests that the influence of prior scientific knowledge on academic performance in physiology courses may be more complex than previously thought.
In our study, 99% of the students from the College of Education were majoring in either kinesiology or physical education; consequently, they would not be a representative sample of the total student population of this college. Because of their career interests, however, they should have had the background and motivation necessary to learn general principles of human function. Unfortunately, other demographic, academic, and science achievement data were not collected in our study. Therefore, we cannot determine what other factors besides college affiliation are associated with academic performance in an advanced-level course in human physiology. We now know, however, that many students enrolled in the College of Education at the University of Kentucky have serious deficiencies in their comprehension of the scientific principles and concepts necessary to understand general human physiology. If similar findings are found in other study populations, special attention would have to be given to the scientific education and training of students enrolled in Colleges of Education, particularly to those students expected to have a reasonable knowledge of human function. This outcome would support previous conclusions that different teaching programs for science education will be necessary depending on characteristics of the targeted students (8, 9, 12), and it would justify a more focused search for predictors of science achievement in this group of students.
Acknowledgments
We are grateful to Daniel Richardson for helpful comments on this paper, and to Henry Hirsch for sharing class records from the semesters when he was the course director of PGY 412G.
Address for reprint requests and other correspondence: C. E. Ott, Dept. of Physiology, College of Medicine, Univ. of Kentucky, Lexington, KY 40536–0298 (E-mail: cott{at}uky.edu).
Received for publication November 7, 2001. Accepted for publication July 31, 2002.
REFERENCES
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