You have sent out interview invitations, but most of the people who respond completed the programme. Your sociology thesis at a university in Poland also needs to cover people who left early. Before booking more interviews, identify the gap in your sample and work out how to report it in your methodology chapter.
Separate eligibility criteria from recruitment channels. The criteria tell you whether someone's experience is relevant to your research question. A channel determines how the invitation reaches them. If an important perspective is missing, first check whether your current channel is likely to reach the people who could offer it.
Set the criteria before sending the first invitation
In this fictional master's project, a student asks how people who completed a first-year peer mentoring programme and people who left early describe their decision to stay or leave. She studies one programme over one semester. She is interested in the experiences of participants who had already met with a mentor.
- Inclusion criteria. Adults who joined the programme in their first year during the semester under study and attended at least one meeting with a mentor.
- Exclusion criteria. People who signed up but never met a mentor, mentors themselves, and people from other rounds of the programme. Leaving before the first meeting could be a research question of its own.
- Contrast to capture. Completing the programme as planned or leaving early. If someone is still taking part, do not classify them as having left. Recruitment for this project starts after the programme ends.
- Unit and method. One individual interview per person. People volunteer and interviewees are selected using the criteria defined beforehand. A sign-up form does not create a random sample.
At the planning stage, a short worksheet is enough. Record the criterion, how you will check it, whose perspective is missing and which channel you could try next. Initial screening in this example only needs self-confirmation of being at least 18, the programme round, confirmation of at least one meeting and self-reported completion status. The reason for leaving comes up in the interview, so it is not a condition for being invited. Palinkas and colleagues describe criterion sampling and strategies that deliberately capture relevant differences between cases.
Identify the missing perspective after the first round
An announcement in the programme's active channel led to five interviews with people who completed the mentoring and one with someone who left. That interview describes a timetable change. The material is too narrow to address the different circumstances of leaving that the project asks about. Reposting the same invitation in the same place may keep favouring people still connected to the programme.
Decision log after six interviews. With the channel administrator’s permission, a second invitation went out through a general announcement channel for the cohort. It invited people who had left before the programme ended. Volunteers contacted the researcher directly. The administrator did not share participants’ contact details. The eligibility criteria and interview guide stayed the same. That channel led to two further interviews with people who had left.
Log the date of the change, the reason, the channel, the criteria and the number of interviews you completed. You can also record known refusals or withdrawals if you track them. With a public announcement, a lack of replies gives you no reliable count of refusals or response rate because you do not know how many eligible people saw the invitation.
Explain why you stopped recruiting
Malterud, Siersma and Guassora's information power model considers five elements: the scope of the aim, the relevance of participants' experience, the use of theory, the quality of the interviews and the analytical approach. In a project on one round of a mentoring programme, detailed accounts of decisions in both groups matter more than the total number of interviews. Comparing two groups still requires material from each, even if accounts in one group are starting to repeat.
After the second round, the student checks her notes for accounts of how the decisions unfolded and for specific situations described by both groups. The extra interviews bring up mismatched expectations about the mentor's role and difficulties finding a time to meet. The student has material to compare the accounts from that round of the programme, but only three accounts come from people who left. That supports a narrow interpretation. If you stop mainly because of a deadline or limited access, state that reason directly.
Example for the methodology chapter
We used purposive sampling to recruit adults from one round of the programme who had attended at least one meeting with a mentor. The first invitation, shared in the programme's channel, led to five interviews with people who completed the programme and one with a person who left early. To better capture the latter perspective, we shared a second invitation through the cohort's general announcement channel and retained the eligibility criteria. We conducted eight interviews in total, three with people who left. Recruitment ended once we had accounts from both groups of how their decisions unfolded. The conclusions relate to the accounts collected. Voluntary participation and the small number of interviews with people who left limit the comparison.
If one group is still missing from your own study, say which group and why, and keep the findings within the material you have. After collecting the interviews, the next task is analysis. See How to analyse interviews for a thesis: from transcription to analysis.
Check the plan against what actually happened
- Do the criteria match the question, and can readers tell who the study did not include?
- Can you tell which channel led to which interviews and why you changed the invitation plan?
- Do the counts in your paragraph match the sample description, and do your notes show why recruitment ended?
- Do your conclusions cover the experiences you collected without estimating how common they are at the university?
Questions about interviews and sample limitations
What should I send for the analysis of interviews in a sociology thesis?
Send anonymised transcripts, the interview guide, the aim and research questions, and a description of participant selection. Include the adopted analysis method and the supervisor's comments, if you have them. Based on this, I will determine the scope of organising themes, summarising statements, and editing the chapter.
How does thesis scope differ from study limitations?
Scope defines the deliberately chosen problem, evidence, population and period. Limitations explain how design features or difficulties restrict interpretation. An omitted topic is not automatically a flaw; the important question is whether the conclusions stay within the stated scope.
How can I connect a limitation to its effect on the conclusions?
Identify a specific feature of the procedure, the finding or claim it affects, and the consequence. Then explain what you actually did to address it and what remains uncertain. A generic list mentioning sample size and time pressure is not enough.
References
- Malterud, K., Siersma, V. D., & Guassora, A. D. (2016). Sample Size in Qualitative Interview Studies: Guided by Information Power. Qualitative Health Research, 26(13), 1753-1760. DOI: 10.1177/1049732315617444
- Palinkas, L. A., Horwitz, S. M., Green, C. A., Wisdom, J. P., Duan, N., & Hoagwood, K. (2015). Purposeful Sampling for Qualitative Data Collection and Analysis in Mixed Method Implementation Research. Administration and Policy in Mental Health and Mental Health Services Research, 42(5), 533-544. DOI: 10.1007/s10488-013-0528-y
Discuss your sample and methodology chapter
Tell us where you are in the project. Send your research question, criteria, recruitment plan or an aggregate summary of completed interviews. We can discuss whether you need help planning the sample or describing how the study actually ran.
