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We aimed for a minimum of 10 interviews. From earlier experiences of interviewing CS1–Imp–Pyth
students for another project, we knew that far from all of the invitees would agree to being interviewed.
The total number of invitations thus significantly exceeded that of the interviews we needed.
Invitations
Again wishing to introduce variation, we sought data from different phases of the course, with some
interviews being conducted nearer the beginning of the course and some at the end. We decided to invite
students in stages, adapting to the situation as we went along, depending on the acceptance rate of the
invitations and the early stages of analysis.
We sent the invitees a fairly informal email that invited them to participate. Students who did not
answer the invitation were sent another email a few days later; those who did not respond to this one
either were not approached again.
The invitations stressed that the interviews were not a part of CS1–Imp–Pyth and that they would be
handled confidentially. It was explained that the interviews were about the course assignments, but VPS
was not singled out as a topic.
The participating students received two movie vouchers as remuneration for a half-hour interview.
In total, we invited 31 students, of whom 11 accepted the invitation: 4 students around the fourth
week of the course, 5 around the sixth week, and 2 around the eleventh week. In our estimation, the set
of eleven interviewees satisfied our goal of ‘variety with an emphasis on strugglers’. Six of the interviewees
were female, five male. Most were around 20 years of age; one was an older student. Only one of the
students had prior programming experience beyond the quick brush with Visual Basic that some of the
other interviewees had had.
Interview (semi-)structure
The interviews were semi-structured (see Section 17.2 above), and involved a great deal of improvisation.
The following gives a general feel of how the interviews progressed. Specific interviews differed in their
details.
Each interview started with introductions of the participants. We made a conscious effort to keep
the atmosphere casual and conversational, and the interviewee relaxed. One interviewer invited the
interviewees to his office, the other interviewer arranged the interviews on the ‘neutral ground’ of a small
meeting room. During many interviews, we offered a selection of soft drinks and water for the interviewee.
We asked the students for permission to record the interview. The interviewer briefly explained that
our research aims to improve the teaching and learning of programming, and reiterated that the interview
would be treated confidentially and anonymously, and would not affect their course grade.
The interviewer then directed the conversation towards the course assignments and towards the VPS
assignments in particular. Once the topic of VPS was mentioned, the interviewer suggested that it would
be easier to discuss it through a concrete example. He then asked the interviewee if they would mind
showing and discussing how they work on a VPS exercise on a computer provided by the interviewer.
It was suggested to the student that they work on the next VPS exercise from CS1–Imp–Pyth that
they had not previously done. Failing that (because the student had already done all the assignments they
had the prerequisite background for), we suggested one of a selection of small VPS exercises prepared for
the purpose of the interviews.
The interviewee mostly worked on the exercise without help from the interviewer. We only gave small
hints for solving the exercise when the learner got completely stuck, and only after discussing what the
problem was. On occasion, if an exercise seemed to be too difficult, we switched to a simpler example
program before returning to the original exercise.
Much of each interview focused around the VPS task. The student would work on the exercise,
thinking aloud. Frequently, we would ask questions about a pertinent topic. A discussion, sometimes
lengthy, sometimes short, would ensue before the student returned to work on the exercise. These
discussions would typically start from questions directly related to the VPS exercise, such as “What are
you doing now?”, “How do you think about what you just did there?”, “What do you think about as you
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