Running head: CHEMISTRY PREREQUISITE PATHWAYS
Chemistry Prerequisite Pathways to Biology for
Allied Health Students
Rick Fillman
Institutional Research Analyst
Planning and Research Office
Summer 2010
Chemistry Prerequisite Pathways
Page 2 of 12
Introduction
Chemistry department faculty are interested in how well chemistry
course work prepares Allied Health students for Human Physiology and
Microbiology. The faculty expressed a desire to examine the grade
distributions of biology students according to the nature and type of
their chemistry preparation.
Human Physiology and Microbiology enrollments from spring 2007
through fall 2009 were examined. This time span includes three
spring terms, three fall terms, and the intervening summer sessions –
basically a three year period. This nets about 2100 student
enrollments in Human Physiology and Microbiology. The table below
shows the number of sections and the enrollment count for the terms
examined.
Some of the enrollments are repeat enrollments. Because this inquiry
is about student preparation, only first-time course enrollments are
analyzed. The preparation of repeaters might be affected by their
experience in the course the first time around. Prior enrollments in
Human Physiology and Microbiology were identified using the Cabrillo
Research Data Warehouse. For the time period examined, about 15%
of Human Physiology enrollments and about 11% of Microbiology
enrollments are repeat enrollments. The charts below show the
population the course sections examined for this study.
Human Physiology (BIO-5) enrollments
2006-07
2007-08
2008-09
2008-09
2009-10
SP 07
FA 07
SP 08
FA 08
SP 09
FA 09
First-time
enrollments
Sections Enrollments
5
170
124
5
166
137
5
172
132
6
194
155
7
234
182
6
205
160
Page 2
Average
Average
First-time
enrollments enrollments
per section per section
34.0
24.8
33.2
27.4
34.4
26.4
32.3
25.8
33.4
26.0
34.2
26.7
Chemistry Prerequisite Pathways
Page 3 of 12
Microbiology (BIO-6) enrollments
2006-07
2007-08
2007-08
2007-08
2008-09
2008-09
2008-09
2009-10
2009-10
SP 07
SM 07
FA 07
SP 08
SM 08
FA 08
SP 09
SM 09
FA 09
First-time
enrollments
Sections Enrollments
4
126
107
2
67
63
4
121
96
4
129
107
2
61
50
4
132
103
4
129
113
2
67
60
4
127
103
Average
Average
First-time
enrollments enrollments
per section per section
31.5
26.8
33.5
31.5
30.3
24.0
32.3
26.8
30.5
25.0
33.0
25.8
32.3
28.3
33.5
30.0
31.8
25.8
The prerequisite CHEM course records are aligned according to the
term completed, and then filtered such that only the prerequisite
course work that was completed prior to a student’s first enrollment
into Human Physiology or Microbiology, respectively, are included in
the analysis.
Prerequisite pathways
Preparation in biology is a requirement for Allied Health majors. In
addition to Human Anatomy (BIO-4 at Cabrillo College), students in
Nursing, Dental Hygiene, and Radiologic Technology are required to
take Human Physiology (BIO-5), and students in Nursing and Dental
Hygiene are also required to take Microbiology (BIO-6). Both
Microbiology and Human Physiology, in turn, require coursework in
Chemistry, so the prerequisite path for Allied Health majors is
considerable.
The Chemistry prerequisites for BIO 5 and BIO 6 are the same;
however there are several possible pathways. A student can meet the
prerequisite by successful completion of either CHEM-2 (Introduction
to Inorganic Chemistry [4 units]), CHEM-30A (Inorganic Chemistry for
Health Occupations [4 units]) or CHEM-32 (Chemistry for the Allied
Health Major [5 units].
Beyond the Biology prerequisites, to complete their program, Dental
Hygiene and Nursing students may also be required to take the CHEM30B (Introductory Organic Chemistry and Biochemistry for Health
Occupations [4 units]). Although CHEM-30B is a not prerequisite for
either of the Biology courses, as it is a program requirement, many
students will have already completed this course by the time they take
Page 3
Chemistry Prerequisite Pathways
Page 4 of 12
Human Physiology or BIO6. Though not a prerequisite, CHEM-30B will
be treated as one of the chemistry courses which prepares a student
for Biology.
Finally, there are some sections of CHEM-30A which are on an
alternative schedule; these sections meet in an all-day format on
Saturdays. The faculty were interested in separately examining those
students who met the Biology prerequisite via the Saturday course
offerings. [A list of the Saturday sections is found in the Appendix.]
Five main prerequisite patterns
Although the original inquiry was in regard to Allied Health students’
preparation for the Biology courses, in order to gain the best possible
perspective on students’ preparation for Biology, this study will
examine the preparation of all students completing Human Physiology
and Microbiology sections. This will include students who prepare for
Biology by taking CHEM-2. It is noted that Allied Health majors
typically do not use this route. In the list that follows, N represents
the number of students in the Human Physiology or Microbiology
cohorts, respectively, with the prerequisite course-work noted. The
five groups to be examined are students who met the Biology course
prerequisite by way of:





Successful
Successful
Successful
Successful
Successful
completion
completion
completion
completion
completion
of
of
of
of
of
CHEM-30A only (N=460/358)
a CHEM-30A Sat. sections (N=74/56)
CHEM-32 (N=58/60)
CHEM-2 (N=56/57)
CHEM-30A and CHEM-30B (N=51/46)
There will be a few students whose pattern of preparation does not
match any of the categories, necessitating a sixth category of “Other”.
The “Other” category consists of three general groupings: students
whose preparation is a mix of Cabrillo chemistry courses that do not
match any of the above patterns, students whose preparation can be
tracked to an equivalency which has been recorded in the student
system (presumably entered by a counselor evaluating either a
transcript from another college or the results of an AP or IB exam), or
students whose preparation simply cannot be determined from the
available data. [See the Appendix for more detail regarding this
group.]
Page 4
Chemistry Prerequisite Pathways
Page 5 of 12
Success and grade distributions
Of all the student grades in Human Physiology and Microbiology
sections studied, there were two “incomplete” grades, which were
omitted. There was one instance of a student with a grade of “CR”
(for “pass”). This grade was re-coded to a grade of “C” for purposes
of simplifying the grade distributions. The “NC” (no-credit) grades
were more numerous, and were left unchanged.
The average success rate (student received a grade of A,B, C or
“Pass”) for courses in the Biology department as a whole hovers
around 75% (as documented in the Cabrillo College Fact Book,
Program Planning Data). There is some variation in the success rate
among courses. The course success rate [all enrollments] for Human
Physiology (BIO-5) is 71.8%, somewhat below the department
average, while the course success rate for Microbiology (BIO-6) is
78.8%, somewhat above the department average.
What about variation according to the Chemistry prerequisite? The
following charts show the success rate for first-time enrollees in
Human Physiology and Microbiology according the type of chemistry
preparation.
Human Physiology (BIO-5)
Success by Chemistry Preparation
100%
85%
82%
80%
72%
70%
66%
67%
60%
40%
20%
-3
0A
,
Page 5
th
er
O
C
H
EM
-3
0B
C
H
EM
-3
0A
_S
at
C
H
EM
-3
2
-3
EM
H
C
EM
H
C
C
H
EM
-2
0A
0%
Success
Chemistry Prerequisite Pathways
Page 6 of 12
Human Physiology (BIO-5) Success by
Chemistry Preparation
Preparation Headcount Success Rate
CHEM-2
56
69.6%
CHEM-30A
460
72.4%
CHEM-30A, CHEM-30B
51
82.4%
CHEM-30A_Sat
74
66.2%
CHEM-32
58
67.2%
Other
183
85.2%
Microbiology (BIO-6)
Success by Chemistry Preparation
100%
80%
84%
80%
75%
85%
80%
93%
60%
40%
20%
O
th
er
-3
2
H
EM
C
-3
0A
_S
at
0B
C
H
EM
EM
-3
-3
0A
H
EM
-3
0A
,C
H
Series1
C
H
EM
C
C
H
EM
-2
0%
Microbiology (BIO-6) Success by Chemistry
Preparation
Preparation Headcount Success Rate
CHEM-2
57
75.4%
CHEM-30A
358
80.2%
CHEM-30A, CHEM-30B
46
93.5%
CHEM-30A_Sat
56
83.9%
CHEM-32
60
80.0%
Other
223
84.8%
Page 6
Chemistry Prerequisite Pathways
Page 7 of 12
As might be expected, for both Human Physiology and Microbiology,
the numerically largest group, the group with CHEM-30A preparation,
comes close to matching the respective average course success rates.
In both cases, the cohorts that exceed the course success average are
the CHEM-30A-CHEM-30B preparation group and the “Other” group.
The groups whose preparation consisted of CHEM-30A Saturday
sections showed a lower-than-average success rate for Human
Physiology, but a higher-than-average success rate for Microbiology.
The grade distributions tell a more nuanced story. For both Human
Physiology and Microbiology, the best performing students (as defined
by earning a grade of A) are those from the CHEM-2 and the “Other”
preparation groups. The following are the grade distributions by type
of CHEM preparation for Human Physiology and Microbiology:
BIO-5 Grades by CHEM Preparation
45%
CHEM-2
CHEM-30A
CHEM-30A, CHEM-30B
CHEM-30A_Sat
CHEM-32
Other
40%
35%
30%
25%
20%
15%
10%
5%
0%
A
B
BIO-5
CHEM-2
CHEM-30A
CHEM-30A, CHEM-30B
CHEM-30A_Sat
CHEM-32
Other
C
A
35.7%
21.5%
29.4%
24.3%
31.0%
42.6%
D
B
25.0%
30.2%
33.3%
25.7%
27.6%
30.6%
Page 7
C
8.9%
20.7%
19.6%
16.2%
8.6%
12.0%
F
D
NC
F
3.6%
4.6%
7.8%
1.4%
3.4%
1.1%
NC
1.8%
4.3%
3.9%
4.1%
1.7%
1.6%
1.8%
1.5%
0.0%
0.0%
3.4%
0.5%
W
W
23.2%
17.2%
5.9%
28.4%
24.1%
11.5%
Chemistry Prerequisite Pathways
Page 8 of 12
BIO-5
CHEM-2
CHEM-30A
CHEM-30A, CHEM-30B
CHEM-30A_Sat
CHEM-32
Other
Totals
A
B
C
20
99
15
18
18
78
248
14
139
17
19
16
56
261
5
95
10
12
5
22
149
D
F
2
21
4
1
2
2
32
NC
1
20
2
3
1
3
30
1
7
2
1
11
W
13
79
3
21
14
21
151
BIO-6 Grades by CHEM preparation
45%
CHEM-2
CHEM-30A
CHEM-30A, CHEM-30B
CHEM-30A_Sat
CHEM-32
Other
40%
35%
30%
25%
20%
15%
10%
5%
0%
A
B
BIO-6
CHEM-2
CHEM-30A
CHEM-30A, CHEM-30B
CHEM-30A_Sat
CHEM-32
Other
BIO-6
CHEM-2
CHEM-30A
CHEM-30A, CHEM-30B
CHEM-30A_Sat
CHEM-32
Other
Totals
C
A
D
B
36.8%
17.9%
30.4%
32.1%
28.3%
40.4%
F
C
31.6%
42.7%
41.3%
35.7%
30.0%
32.3%
D
7.0%
19.6%
21.7%
16.1%
21.7%
12.1%
A
B
C
21
64
14
18
17
90
224
18
153
19
20
18
72
300
4
70
10
9
13
27
133
Page 8
NC
F
NC
3.5%
3.1%
2.2%
3.6%
1.7%
1.8%
1.8%
2.0%
0.0%
0.0%
0.0%
0.4%
D
F
2
11
1
2
1
4
21
W
W
3.5%
1.7%
0.0%
0.0%
1.7%
1.8%
NC
15.8%
13.1%
4.3%
12.5%
16.7%
11.2%
W
1
7
2
6
1
9
1
4
13
9
47
2
7
10
25
100
Chemistry Prerequisite Pathways
Page 9 of 12
In light of the fact that the “Other” group shows evidence of success,
the composition of this cohort begs examination. For both the Human
Physiology and the Microbiology CHEM prerequisites, the largest
component of the “Other” cohort consists of students who show some
kind of equivalency record as having met the prerequisite elsewhere
(about 44% for Human Physiology and about 70% for Microbiology).
The next largest component consists of students whose CHEM
prerequisite course-work at Cabrillo simply did not fit into any of the
five large categories (about 30% of the “Other” group for both Human
Physiology and Microbiology). Finally, there are the Human Physiology
and Microbiology students who prerequisite preparation cannot be
determined (about 27% for the Human Physiology “Others” and about
28% for the Microbiology “Other” groups).
Statistical significance
While the descriptive data presented thus far are accurate for the
specific cohorts that were studied, if these results are to be used to
inform decisions regarding future adjustments to curriculum or
scheduling, then an examination of reliability and consideration of
other possible influencing factors is warranted.
Multiple regression analysis revealed that few of the preparation
pathways are reliably associated with differences in student outcomes.
In other words, the observed differences in outcomes are likely due to
chance variation and not to any consistent difference in student
preparation associated with a particular pathway. However, some
differences were detected for particular preparation pathways; the
CHEM-2 preparation and the Other preparation groups tended to have
somewhat higher grades and somewhat better odds of passing the
Biology courses. Overall, about 2 to 3% of the variation in grades is
predicted by the type of preparation - statistically perceptible, but of
rather weak predictive value.
Attempting to increase the sample size, by pulling in an additional five
years of data (going back to 2001) did not result in altering the picture.
The type of preparation seems to reliably account for very little of the
variation observed in success and grades. With the benefit of the
larger sample sizes in the larger data set, the analysis uncovers, after
equalizing for other factors [Estimated Marginal Means], that Latino
students from the CHEM-30 Saturday preparation groups are getting
better grades than their counterparts in the other preparation groups.
While evident for both target courses, this tendency was more
Page 9
Chemistry Prerequisite Pathways
Page 10 of 12
pronounced for grades in Microbiology (BIO-6) than for grades in
Human Physiology (BIO-5).
Other factors
When student demographic variables were brought into the analysis,
the predictive value of the model was strengthened. Student ethnicity
had the greatest predictive power when it comes to grades in both
Human Physiology and Microbiology. Ethnicity was coded as
“Underrepresented” or “White/other”. Underrepresented includes
Latino, African American, Filipino, and Native American students; at
Cabrillo, this group is predominantly Latino. The White/other group is
predominantly White, but also includes a few of students of Asian,
decline-to-state, and Unknown ethnicity categories.
Underrepresented students tended to receive lower grades than the
“White/other” group of students. Age contributed to the predictive
model, as well, with older students getting slightly better grades than
younger students. Also, membership in the “Other” prerequisite
preparation group begins to function as a predictor of better grades, as
does the students’ age. The influence of these two factors appears
about equal. Gender, on the other hand, does not appear be
particularly significant. Removing the “W” grades, and repeating the
analysis has the effect of slightly sharpening the model, but not to an
extent that would change any of these patterns. Together, ethnicity,
age and the type of preparation can account for approximately 10% of
the overall variation in grades in Human Physiology and Microbiology.
Summary
There are many factors that can influence student performance; and
many of these our beyond our ability to track. While some differences
were found, on the whole, the type of Chemistry prerequisite
preparation was not found to be a major factor in influencing grades in
Human Physiology or Microbiology courses. Nonetheless, perhaps
these data regarding the course taking patterns of Allied Health (and
other) students in Chemistry and Biology will prove informative for
faculty in the departments.
Page 10
Chemistry Prerequisite Pathways
Page 11 of 12
Appendix
Saturday CHEM-30A Sections
SP 07
FA 07
SP 08
FA 08
SP 09
FA 09
CHEM-30A
CHEM-30A
CHEM-30A
CHEM-30A
CHEM-30A
CHEM-30A
50179
53008
55388
59447
60559
63022
Composition of the "Other" cohort -BIO-5
Courses taken
None (at Cabrillo)
None (at Cabrillo)
None (at Cabrillo)
None (at Cabrillo)
None (at Cabrillo)
None (at Cabrillo)
None (at Cabrillo)
None (at Cabrillo)
CHEM 30A
CHEM-2, CHEM-30A
CHEM-2, CHEM-30A, CHEM-30B
CHEM-2, CHEM-30A_Sat
CHEM-2, CHEM-30B
CHEM-30A, CHEM-2
CHEM-30A_Sat, CHEM-30B
CHEM-30B
CHEM-30B
CHEM-30B
CHEM-30B, CHEM-2
CHEM-30B, CHEM-30A_Sat
CHEM-30B, CHEM-32
CHEM-30B, CHEM-32
Equivalences
Unknown
CHEM2
CHEM2, CHEM30A
CHEM30A
CHEM30A, CHEM2
CHEM30A, CHEM30A
CHEM30A, CHEM30B
CHEM30B, CHEM30A
CHEM2
CHEM30A
CHEM2
CHEM30A
Page 11
Headcount
59
50
2
38
2
1
2
1
1
2
1
1
3
5
2
35
1
2
3
5
1
1
27.1%
22.9%
0.9%
17.4%
0.9%
0.5%
0.9%
0.5%
0.5%
0.9%
0.5%
0.5%
1.4%
2.3%
0.9%
16.1%
0.5%
0.9%
1.4%
2.3%
0.5%
0.5%
Chemistry Prerequisite Pathways
Page 12 of 12
Composition of the "Other" cohort -BIO-6
Courses taken
None (at Cabrillo)
None (at Cabrillo)
None (at Cabrillo)
None (at Cabrillo)
None (at Cabrillo)
None (at Cabrillo)
None (at Cabrillo)
CHEM 30A
CHEM-2, CHEM-30A
CHEM-2, CHEM-30A, CHEM-30B
CHEM-2, CHEM-30A_Sat
CHEM-2, CHEM-30B
CHEM-30A, CHEM-2
CHEM-30A, CHEM-2, CHEM-30B
CHEM-30A, CHEM-30B, CHEM-2
CHEM-30A_Sat, CHEM-30B
CHEM-30A_Sat, CHEM-30B
CHEM-30B
CHEM-30B
CHEM-30B
CHEM-30B, CHEM-2
CHEM-30B, CHEM-2
CHEM-30B, CHEM-30A_Sat
CHEM-30B, CHEM-30A_Sat
Equivalency
Unknown
CHEM2
CHEM2, CHEM30A
CHEM30A
CHEM30A, CHEM2
CHEM30A, CHEM30A
CHEM30A, CHEM30B
CHEM2
CHEM2
CHEM2
CHEM30A
CHEM2
CHEM2
Page 12
Headcount
74
62
1
40
3
1
2
1
2
1
1
4
2
1
1
1
1
36
6
6
7
1
6
1
28.4%
23.8%
0.4%
15.3%
1.1%
0.4%
0.8%
0.4%
0.8%
0.4%
0.4%
1.5%
0.8%
0.4%
0.4%
0.4%
0.4%
13.8%
2.3%
2.3%
2.7%
0.4%
2.3%
0.4%