D. K. Lewis and W. A. Wolf Colgote University Hamilton, New York 13346
I
Keller Plan lntroduttory Chemistry Students' performance during and after the Keller experience
Recently, several descriptions of self-paced auto-tutorial, or "Keller Plan" courses in chemistry have appeared (I), including one by the present authors (la). However, most of those detailed course descriptions, including our own, have lacked detailed evaluations of the long term educational accomplishments of those courses. Results have consisted largely of assessments of student morale and attitudes, and usually also of final exam results. This academic year (1973-74) is now the third in which the Chemistry Department a t Colgate University has offered students the choice of taking the Introductory Chemistry course via either the-traditional lecture/discussion method in a section of 2&30 students or via the Keller Method. We feel that we now have sufficient data to evaluate the effectiveness of the Keller Method relative to the traditional lecture/discussion section approach in terms of (1) teaching of facts, principles, techniques, and attitudes that can be evaluated by the time the student has completed the course, (2) preparing students for more advanced courses in chemistry, (3) attracting chemistry majors, and (4) efficiency of the program. In this paper we present our data and conclusions. The Keller Plan Course-Summary of Operation Details of operation of our Keller-type course as offered during the 1971-72 year were given in our earlier report (la). Since that time the basic approach has remained the same, with the exception that various formulas for determining grades in the course have been tried. Each semester's material is divided into conceptual units-from 15-21 per semester, depending upon the text chosen and range of material covered-and a study guide and half a dozen or so quizzes are written for each unit. When a student feels he has mastered the assigned readings and problems he takes a quiz, usually written, on that material. It is then graded passlfail in his presence by another undergraduate student hired by us as a tutor, or by an instructor. To pass a quiz, a B level performance is required; the student must eventually pass a quiz on each unit before proceeding to the next. The customary grading policy is that a student's semester grade is determined by the number of units passed during the semester-up to a B for completion of all units. All students are required t o take a final examination, the results of which may raise the preliminary grade but will not lower it. Thus, the final exam can only benefit the student. In addition, the lahoratory grade, considered to carry one-fourth the weight of the course, can also influence the final course grade. During the Spring, 1972 semester only, we offered the additional option that a grade above a B could he obtained by completing additional Keller units, intended to be more difficult, a t an A level. The effect of this different grading criterion is clearly visihle in the statistics presented in the next section. Comparative Performance in Introductory and in Organic Chemistry Distributions of grades awarded after completion of the first semester (101) and second semester (102) of Intro-
ductory Chemistry in 1971-72 and 1972-73 via the Keller or lecture/discussion methods are given in Table 1. The "Grade point average" figures are based on A = 4.00, B = 3.M. etc. In each semester, the same final exam was used for both groups. Students may, if they wish, take Chemistry 101 by one method and then elect to take 102 bv the other. Table 1 indicates that in both 1971-72 and i972-73, substantial numbers of students enrolled in the Keller section of 102 after having taken 101 via the regular method. Since only 19 persons took 101 via the Keller plan in Fall 1971, more than three-fourths of those who took 102 via the Keller method in Spring 1972 had been in regular sections of 101. In the 1972-73 year, nearly half the students in the Keller section of 102 had taken 101 via the Keller method. Virtually no students in either year took 101 via the Keller method and then elected a regular section of 102. Tahle 2 gives the grade distribution for students who took both semesters via the Keller method, both semesters in regular sections, or one semester of each. The course which normally follows the year of introdnctory chemistry in our curriculum is Organic Chemistry, 263 and 264. Last year (1972-73) about 40% of the students in organic chemistry had taken at least one semester of introductorv chemistrv via the Keller method. Performance in both-semesters-of organic chemistry by these students is compared with performance of students who took introductory chemistry solely in lecture/discussion sections in Tahle 3. Discussion The data in Tables 1 and 2 show a remarkable consistencv in the comoarative oerformances of the Keller and regular sections on common final examinations, and sunaests the conclusion that the Keller method is about as effective as the lecture/discussion approach in teaching the facts and skills that are evaluated by the ACS multiple choice exams. For this conclusion to he unassailable, we would have to establish that the two groups of students being compared are about equal in ability and motivation. This task is virtually impossible, hut we do have Toledo Chemistry Placement Tests and CEEB Mathematical Scholastic Aptitude Test Scores for most students. These scores have proved moderately reliable as predictive indicators of performance in introductory chemistry. Except in the fall, 1971semester, when the Keller section students averaged somewhat above the others in both indicators, there has been no significant identifiable difference between the average scores of the two groups. We do know that the Keller plan has the desirable effect of attracting students with some advanced preparation, since they can pass rapidly over any repetitious material, and i t also attracts a majority of the upperclass students. However, we also feel that this system attracts some stu-
Presented at the 5th Northeast Regional ACS Meeting, Rochester, N.Y., October 1973. Volume 51. Number
10. October 1974
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Table 1. Grade Distribution in Keller and Regular (Lecture/Discussion) Sections of Introductory Chemistry 101-Fall, 1972 102Spring. 1973 102-Spring, 1972 101-Fall,1971 Keller A
6
B C
11 1 1 0
D F
Total students
Grade point average % Correct on final exam
Regular
26 35 36 22 7
-
-
19 3.16 50
126
KeUer
Regular
Keller
Regular
KeUer
37 23 7
9 8
37 35 39
1
15 20 14 2
2
8
1
1
3
4
17 49 11 2 0
-
-
-
-
69
52 2.73 4Ss
2.78
43
123
3.28
2.40
45'
39
21
61
Regular 12
20
13 6 0 -
79
51
2.78
3.04
2.71
65
76'
806
ACS 1970 Form Generalchemistry Exam; number is % of msrimumposaiblesooreafter sdjvstment of raw scoreto compensate for random guessing. a ACS 1973 Form General Chemistn, Exam.
Table 2. Comparison of Grades Awarded to Students in lntroductory Chemistry 101 and 102. 1972-73 Students in Students in Regular Seaions Keuer SeetiStudents in Both Semeatete
in1
P TOM Grade p i n t average % Corred on hnal exam
...
KeUer
102
"IF
102
...
...
... -
-
33
33
68
3.03 75
37 2.97 69
37 3.06 76
-
3.00
-
Both SBmeste*J 102
101
... 51
...
51
2.84
2.71
69
80
Students receiving an F in Chemjatry 101 eodd not continue on to 102.
dents a t the other end of the scale who are reluctant to he in a regular section in which they will he competing more directlv aeainst other students. This factor tends to compensate for the competitive edge of the Keller plan in attzactine good students. Thus, a t least during the first semesterrtLe two groups appear to be comparable. For the second semester, however, we may have inadvertantly built into the Keller program a student selection factor, due to our policy of granting grades above the Blevel only for superior performance on a final examination. The middle column of Table 2 shows that the group who switched from a regular to the Keller section for the Spring semester in 1972-73 consisted mostly of B students. The students who received an A in a regular section elected not to take the Keller plan, perhaps perceiving (incorrectly) a decreased likelihood of getting another A. This is unlike the Spring 1972 semester, when a large majority of students who had received A grades in regular sections in the Fall switched to the Keller section in the Spring. Most of the students who received C or D grades first semester in regular sections elected to continue in regular sections. Statistics in Tahle 3 indicate that students who had taken introductorv chemistrv hv the Keller d a n in 197172 performed as well in orgakLchemistry d;ring 1972-73, within the limits of uncertainty in the statistics, as did students who had been in small lecture/discussion sections. The conclusion t o be drawn from this, that the two formats are equally effective in preparing students for organic chemistry and perhaps also for more advanced chemistry courses, is placed in question by the fact that we do not know to what extent performance in organic chemistry depends upon the quality and effectiveness of the introductory chemistry experience. We do know that there is a high correlation between grades in introductory and organic chemistry at Colgate. This must of course depend to a large extent upon native intelligence and motivation; but we also feel that there is sufficient carryover from introductory to organic chemistry for a greatly superior or inferior ~ r e ~ a r a t i oinn the former to show up in performance in the fatter. An addnional but less accurate basis for comparing the two methods is nrovided bv verbal feedhack. A oolline of students who have gone o n t o organic chemistry k t e r caving taken introductory chemistry by the Keller method indicates that they perceive their preparation to be equal
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666
/ Journal of Chemical Education
Table 3. Comparative Performance in Organic Chemistry (263, 264) by Students from Keller and Regular Sections of Introductory Chemistrv (102) KeUer Section,
Chemistr" 102 Chemistry 102 Grade Point Average Spring, 1972 Number of Students Number who took organic Chemistry 1972-73 Grade point Average in Chemistry 102 of Students who took organic Chemistry 1972-73 Grade point Average in Organic Chemistry 263, snd 264
Regular Seetion chemistr" 102
2.73
3.28 69
52
44
38
3.50 2.91 2.87
3.03
2.93 2.91
to or better than the preparation of the students who were in regular sections of 101 and 102. It is of particular importance that both the actual and the perceived quality of the preparation in chemistry offered in a Keller plan course be comparable to the regular type of course, since a high percentage of our students are professionally oriented and expect to compete for admission to graduate, medical. and dental schools. The grading system inherent in the Keller plan results in a skewed distribution of mades rather than a Gaussian distribution, as has been w z l documented previously (2), and as is clearly visible in Tahle 1. In our experience, the peak in the distribution curve has come at the highest grade that could be earned by completing units only. Thus, the disparity in grade distribution between Keller and regular sections was more pronounced in Spring 1972, when students could earn un to an A made bv com~letine more units, than in other semesters. Some earlier proponents of the Keller method have defended awarding hipher grades to Keller students, despite equal or poorer final examination performance, with the argument that the Keller students were used to taking exams without time limits, with passlfail grading, with verbal interaction during the grading, and with the opportunity to retake any exam failed. Since these students would undoubtedly have been exposed to the pressure of finite time limit exams in other courses in high school or college, this seems to us a specious argument. However, in our case there has been evidence, corroborated by the students,
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that some Keller students who comnleted the units and laboratory assignments and who were thus assured of a R grade elected to devote all their time studying for final examinations in other courses rather than devote the extra time and effort necessary to raise their chemistry grade above a B. Thus, it is perhaps surprising that the Keller students did as well, on the average, as the other students on the final exams. In a practical sense, the Keller grading system creates a problem, particularly if students are to be allowed to earn an A grade in a course solely by completing units. The quizzes must be difficult enough to ensure that complete mastery of the material has been accomplished, yet not too difficult lest some students never get beyond unit one and give u p from discouragement. Mastery is easy t o define when the material consists of facts to he memorized, but more difficult when it consists of concepts which we will expect a student to he able to apply under a variety of situations. We continue to feel that our policy of testing for mastery of material a t the B-level, and requiring extra evidence of mastery via a final examination for any grade hieher than a B. results in a Keller-type course which avoids discourag&nent and the resulti~procrastination, and which gives students in our Keller and regular sections approximaiely equal rewards for equal learning. We owe our students fair and consistent grading, and should not force them into or out of a mode of learning due to real or perceived grading inequities. A final statistic may be offered. There are currently 11 students enrolled in the junior-level physical chemistry course who took their introductory chemistry a t Colgate during the 1971-72 or 1972-73 years when the self-paced option was offered. Six of those eleven took both semesters by the Keller method. Whether or not the Keller experience has attracted a few extra students to major in chemistry we cannot say for certain a t this time. We can say that the burgeoning populations of students in our advanced courses, predicted hy some of our colleagues, have not materialized. This year the total enrollment in physical chemistry (16) is about what it has averaged in recent years. A word or two is in order about the efficiency, or staff time requirement, of the Keller plan. In our experience, the couke demanded a much greater than normal input of time and energy during the first year when the course materials had to-be prepared and unforeseen organizational problems had to be worked out. We confidently predicted that the second year would he less demanding. However, we decided to change to a more lucid, readable text; so the process of material preparation had to begin over again. Now, in the third year, we feel we have a more realistic outlook. The instructor responsible for the Keller section of introductory chemistry is responsible for two to three times the number of students in a regular section; thus there can he an overall reduction in faculty load to ~~~~
~
~
compensate for the wages paid t o tutors. But with the extra laboratory sections to oversee, the continual need for revising and updating materials, and the need to stay "close to the students," the demand on the instructor's time is a t least as great as if he were teaching a regular section. After all unit assignments and quizzes have been written, the Keller plan can become more efficient than most other formats if all short cuts are used. However, if this aspect is what makes the plan most attractive, we would suggest not using i t in order to avoid a well deserved student rebellion. If the plan is used only t o avoid contact and teaching, students will recognize this. Along this line, it seems important to us that in implementing the plan, the instructors must get to know the students as well as the tutors, and take an active interest in their welfare. This involves following students' progress, being readily available in the testing areas for discussion about quizzes, problems, etc., and, if you will, providing a role-model of what it means to he a chemist. Students' overall morale and the perception of what they are getting in return for their tuition is greatly enhanced by the instructor's presence and attitude. It should he added that it is more rewarding to the instructor, as well as more time consuming, to be involved with the day-to-day functioning of the program. Conclusion Recently there have appeared some articles critical of the behavioral school in general (3) and the Keller plan in particular (4). We agree that this plan is not a cure-all for the inherent drawbacks in other educational methods, nor is it really much less demanding of either students or faculty than the traditional methods-in fact i t is initially more demanding of faculty. We further recommend that the method should not be forced on students who are wary of it, or on faculty who are not convinced of its value or who are unwilling or unable to devote the time necessary to make it work. Nevertheless, we feel that our Keller plan option in introductory chemistry continues to be a valuable addition to our program, one which many of our students find more satisfving and which allows some of us to use our abilities as teachers more effectively. The availability of both Keller and lecture/discussion methods of learning suits a far greater fraction'of students and faculty than either method alone. Literature Cited (1) (a) hluis, 0. K., Wolt W. A., J. CHEM. EOUC.,S0,51 113731; (b)Elton, L. R. 8.. Baud, D. J.. Nuttsll. J.. and Stace, B. C.. Chem. Bril., 9. IM 11373); Leo. Micah Wei-Ming, J. CHEM. EDUC., 50, 49 11973); White, John M., C I w . John S.. andMcAlliater. Jemme W.. J.CHEM. EDUC.,49.772(1972). (2) Kellec. F. S., J. A p p l Behaumral Anolyris, 1, 79 (I=): M m m J. W.. Mahan. J. M., and Rite, C. A., P~ycholodcolHeporn 25.887 11969). (3) Mellon. Edward K.. J. CHEM. EDUC., SO, SJO (1973); Blasted, R. C., J. CHEM. EDUC.50, 580 (1973l:\Volke, R.C..J-CHEM. EDUC.,SO,99(1973). (4) Yound, David. Chrm. Brit., 9.168l1973).
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