Q: Can I use the same participants' sample for doing a test and retest in a focus group study?

Detailed Question -

I am in the early stages of my Masters by Research. My research is centred around the development of a substance use prevention program for young people aged 12-15, using and culturally adapting some educational materials in use elsewhere in Europe. I am currently trying to devise a plan on how best to test the materials. I would like to adopt a heuristic approach, whereby I conduct focus groups (FGs) on the unaltered materials, then complete preliminary adaptations based on the FG information, and then retest. So, my query is: am I best to use the same participants' sample for both FGs, and if so, how does this affect the reliability and validity of the data?

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1 Answer to this question

Firstly, it’s interesting to note that you are pursuing a Master of Research (MRes). That would explain the desire to use a heuristic approach for the study, as the MRes degree and the heuristic model have the common element of experimental learning.

Coming to your query, there are two key considerations for the design you are contemplating.

  • Feasibility: An FG study, as you would know, is time- and effort-intensive, requiring careful planning and coordination of location, duration, time, and of course, participants. By your proposed design, you plan to conduct two FGs. Apart from the logistical challenges this implies, you will need to spend considerable time and effort recapping the study when the participants and moderator(s) regroup after the gap. And the longer the gap, the greater the amount of recapping needed.
  • Potential for bias(es): With regard to the reliability and validity of the data, a recall bias could creep in due to the time lag, with at least some (if not all) participants not correctly recalling their responses and/or the reasons for those responses during the second FG. On similar lines, there might be a survival bias, with participants recalling only select information, typically that which stood out in some way. They might then evaluate the program materials through these skewed lenses. Again, there would be considerable effort needed to prevent or limit these biases (such as by having ready access to all the previous responses).

What you may consider doing is having only one FG and using a market research paradigm. For the program materials that you are planning to adapt, you could create a few different adaptations – say, two or three alternatives – based on your hypothesis. After you have sought participants’ inputs on the communication points for the materials, say, in the first part of the FG, you could present these options in the second part to obtain their feedback on these. This would allow you to capture their feedback in a short interval from their initial inputs (rather than the long gap until a second FG) and also address any concerns then and there. Based on their responses, you could then take the set that receives the most favourable response and modify this to arrive at the final version. If needed, you may share the finalized set with the participants later, adding a survey if needed, for final thoughts and comments.

In all, you will need to weigh the practical considerations against the objective of the study to arrive at your final design.

For now, here are some other queries from the site that you may find useful.

Coming back to the MRes, it would seem that you are interested in pursuing research as a full-time career and are using the program to assess if the researcher path and life are indeed for you. That would be a perfectly calibrated way of proceeding. If indeed so, you may wish to check out some of our other researcher connect initiatives.

  • Researchers & Their Stories: Here, researchers share stories about different facets of the researcher life – from struggles to successes – acting variously as support and inspiration to other researchers.
  • Researcher Voice: A social media group (on Facebook), this provides an even more informal way for researchers to connect with and spur on each other.

All the best for the next stages of your study – and career!