Goranka Bjedov, Department of Freshman Engineering, Purdue University
During their freshman year, engineering students at Purdue University were expected to successfully complete a three credit computer programming course. The author was involved with teaching the C Computer Programming class since the fall of 1991, when it was first offered in its full size. ENGR 195A, ``Introduction to C Programming,'' is a class whose enrollment varies between 360 students (in spring semesters) and 940 students (in fall semesters). The class has a reputation as difficult and time consuming. This reputation is well-deserved from both the students' and the instructors' perspective.
The Internet and the World Wide Web have proven to be two tools available to instructors to improve communications, shorten response time to questions, and increase overall learning. These tools can be utilized to facilitate communication between the instructional staff (Teaching Assistants, Undergraduate Assistants and Professors) and standardize grading and information sharing practices between the staff. In particular, we have utilized network information sharing capabilities to post lecture notes, programs, and old exams, as well as provide answers to submitted questions for student use. We have also used this medium to provide Teaching Assistants with answer keys for assignments and exams. These approaches, which have been tested (in different stages) on over 3000 students, have resulted in a greatly improved student performance on the exams and their perception of the course.
During their freshman year, engineering students at Purdue University were expected to successfully complete a three credit hour programming course in either C or FORTRAN programming languages. The author was involved with teaching ENGR 195A - ``Introduction to C Programming'' since the fall of 1991, when the class was first offered in its full size. ENGR 195A is a class whose enrollment varies between 360 students (in spring semesters) and 940 students (in fall semesters). The class has a reputation as difficult and time consuming. This reputation is well-deserved from both the students' and the instructors' perspective.
When run in its full size, ENGR 195A is offered in two lecture sections of 470 students each. The students meet twice a week for one hour for mandatory lectures, and once a week for a one hour optional help session. Additionally, students are divided in laboratory divisions of 40 students each (with one division of 30 students) that meet once a week for a mandatory two hour laboratory session. The lecture sections are taught by professors, while the laboratory sections are supervised by the teaching assistants (typically two sections per assistant).
As with every course, teaching is only a part of the instructional duties in a large class. In a class of 20-40 students, an instructor has a chance of getting to know all of his/her students during the semester, and when the time comes, can feel comfortable assigning their grades. Students have a chance to approach a professor before or after the lecture and have their questions answered, or they can come to office hours. Since the exams are given to all of the students at the same time, there are no advantages or disadvantages. All of the exams can be graded by the same person, assuring fairness.
All of these possibilities disappear in a large class. A professor cannot get to know 470 students. Since the lectures exchange in a 10 minute interval, only a few of the students with questions about the material can have those questions answered, regardless of how many office hours are available. And, at the time when a project is due, it will be impossible to get past all of the other students asking for help. While in-class exams can be given to all of the students at the same time, in-lab exams cannot due to a lack of resources. The lab exams are graded by different people, and although following the same general rules, differences in the grading styles can be important. [4, 6, 7]
Over the four year period, ENGR 195A has experimented with several different ways of determining a student's proficiency in the course material and offering help to the students with difficulties in the course.
In the beginning, the help sessions were organized by demand only, usually on Saturdays before the exams or throughout project times. The office hours by professors and teaching assistants were offered during the regular work hours, and the teaching assistants would schedule their hours so that majority of their students could attend them. The office hours were held in teaching assistants' offices.
Students' performance in the class was measured in several different categories - homework assignments, group projects, in-class exams and in-lab assignments. A relative weight was assigned to each of these categories, and the final grade was determined according to the straight scale.
The problems with this organization were numerous and difficult to correct in the same setup:
The last time ENGR 195A was offered in its full size, in spring of 1995, the course was organized completely differently. In the evaluation part of the course, homeworks were completely dropped from the grading scheme and in-lab assignments were replaced by quizzes. The rest of the course remained essentially unchanged, except that a heavier weight was given to the performance on exams. This approach solved several problems in determining the grades, but major changes appeared in the area of providing help for the students.
The students are automatically scheduled for three lecture hours a week - one of which is an optional help session. Since that hour is entered into their schedules, all of the students are available during that time, and if instructed by their teaching assistant must come to the help session. Typically, students whose current average in the class is below 70%are required to attend the help sessions.
The office hours of the teaching assistants have been moved to the evening, and are held in the computer laboratories. Every evening, there is at least one teaching assistant available for two hours. Additionally, an undergraduate assistant was added to the lab in the evening. Teaching assistants hold their office hours the night before their first lab.
During the day, students with simple problems can send email to a specified account (monitored by the course personnel), and their questions are answered ``immediately'' between 8:00 am and 10:00 pm. Lecture notes, sample code segments and all of the previous semesters' information (including in-lab and in-class exams, and sample solutions) are made available on-line (URL: http://fre.www.ecn.purdue.edu/fre/homes/goranka/engr106/). Since a lot of students have similar questions, a newsgroup was created for the class with the idea that commonly asked questions can be answered through the newsgroup (URL: "news://news.cc.purdue.edu/purdue.class.engr106).
Of all of these changes, the rescheduling of the office hours and availability of immediate help was the most important factor for the students. Interestingly, this arrangement was praised by the students and the teaching assistants alike. By providing sample exams on line, the flood of complaints from the labs scheduled early in the week was stopped, and the discrepancy in their performance on the in-lab exams was completely eliminated.
The laboratory time was completely restructured - instead of an in-lab assignment, the students are given 30-45 minute quiz covering their homework (which is not collected and graded), and after that time they start working on their homework assigned for the following week. Teaching assistants are allowed to give help during the quiz, but since the quiz covers the homework material assigned, the students are penalized for any help received. This reduces the demands on the teaching assistant during the first part of the lab. During the second part of the lab, the students are no longer pressured to complete an assignment in what they may perceive as a short time-frame. Without that time pressure, the teaching assistant is able to aid more students, providing help in a more distributed manner.
To avoid the procrastination problems on the programming projects, students are encouraged to start working early in two different ways: if they turn the project in a week early, it is graded and if any small mistakes are encountered they are allowed to correct them without penalty; and, during the final week of the project assignment the help is offered only for specific (more advanced) areas.
There are several different indicators that the changes have made the class more enjoyable for the students taking it. At Purdue University, students fill out an evaluation form for the instructor in the course, usually during the last week of the semester. The average grade in the evaluation form for the author has risen by 1.2 on a 5.0 scale. Additionally, on the survey where freshman engineering students rate their satisfaction with the classes they have taken during their freshman year, more then 70%of freshman students have rated ENGR 195A (as offered in the final version) as satisfactory or very satisfactory. This increases the original satisfaction rate by more than 15%. [3]
The important thing to note is that the average grade in the course has gone down over the four year period (approximately 0.5 points on the 4.0 scale), while the performance on the exams went up by 8-10%. Significant reason for this trend was the fact that homeworks (which used to count as 20%of the course grade) were not graded any more, and that percentage was taken over by the exams.
From the instructor's standpoint, the course is easier to run. Interruptions outside of scheduled office hours have been minimized. The teaching assistants, whose common complaint used to be that no students are coming to their office hours, but expect all of the help during the regular laboratory time, report that their office hours are well utilized. Additionally, all of the teaching assistants expressed their preference for the evening office hours. Their opinion on the location of office hours (computer labs as opposed to their offices) was divided, although all agreed that the location (computer labs) was one of the reasons for the popularity of the office hours.
The teaching assistants felt that sample corrected in-lab exams were a great help in achieving uniformity in grading. If unsure of how to grade a particular program, they could always refer to a set of graded examples, or contact the instructor and add a particularly difficult/different exam to the graded set. Therefore, any exam significantly different from the sample solutions was graded by the instructor, assuring uniformity and fairness.
By offering all of the lecture notes and sample exams on-line, all of the requests for those materials have been eliminated. The advantage of placing such materials on line, as opposed to the library, is that the materials cannot get stolen, and updating from semester to semester is very simple.
As with every implementation, some parts of the solution did not have a significant impact, while others caused additional problems. In particular, the newsgroup was not as popular for the course related topics as it was for unrelated political discussions. The students invariably found it easier to mail in their question than to check if a similar question has been answered on the newsgroup. Usually, this problem was solved by creating an answer file, and mailing it to the individuals who requested it. If the question was particularly popular, or judged by instructional staff as something important to all of the students, the answer would be made available on-line. These additions were announced in the lectures, and in the message that the students receive when they log on to the computer network. In the future, these questions will be posted as a FAQ (Frequently Asked Questions).
A more important problem was introduced by not grading the homework solutions. Although it was clearly stated that the homework was not optional, and that the purpose of the homework is for the students to learn the material, a lot of students stopped doing it altogether. The only common complaint on the evaluation forms (received from five or more students) was that their grade was hurt because of poor quiz performance. They also concluded that the reason for poor performance on the quizzes was the lack of time spent on the homework, but they explained that they cannot ``waste'' their time on homework that is not graded.
This problem puts an instructor in a difficult situation. It is difficult to justify giving even a part of a grade for something that a significant percentage of the students copy - one could argue that grading of that type encourages cheating. [1,5] While personal responsibility, integrity and engineering ethics must be stressed (and they are), it is clear that it takes more than one semester for students to start abiding by the honor codes in place at most universities. [2, 8] And, while it is possible to dismiss such students and recognize that ultimately they are responsible for their own fate, it is still a professor's duty to try to do everything possible to make students learn the material.
One possible solution to this problem presents itself through the use of the World Wide Web. A professor can create a homework form that each student has to fill out and pass before coming to the lab. The form would ask some questions based on the homework, and a student would be allowed to answer them at his/her own convenience. As soon as the student mails in his/her answers, a computer program on the other end scores their solutions and mails them their score. If the score is below passing level, the student needs to repeat the procedure. The computer program keeps track of all the students who have passed, and before the start of each laboratory session, mails the list of the students who have not completed their homework to the appropriate teaching assistant.