A brief note on theoretical sampling and purposeful sampling: for Housing Studies students

A brief note on theoretical sampling and purposeful sampling: for Housing Studies students (information from perplexity.ai)

My question: "I am interested to conduct semi-structured interview to learn "the opinions of the Hong Kong generation z's on housing affordability". Then, I realize that I need to also consider which sampling method to use: theoretical sampling and purposeful sampling. Please clarify these 2 sampling terms to me in this context."

The reply: "Theoretical sampling and purposeful (also called purposive) sampling are both qualitative sampling methods but differ mainly in their approach and timing relative to data collection and analysis.

Purposeful sampling is a strategy where participants are deliberately selected based on specific characteristics or criteria relevant to the research question. The goal is to gain in-depth information from individuals who are most likely to provide rich insights on the topic, such as generation Z Hong Kong residents with opinions on housing affordability. It is a strategic, judgment-based choice meant to illuminate the phenomenon in detail rather than represent the whole population.​

Theoretical sampling, by contrast, is closely linked to grounded theory methodology. It involves selecting new participants or data sources based on evolving concepts and findings during the research process. Sampling decisions emerge as the theory develops, continuously refining and extending understanding rather than following a predetermined participant selection plan. This means sampling is adaptive and iterative, with cases chosen to explore and test emerging theoretical constructs.​

In your context of exploring Hong Kong generation Z's opinions on housing affordability via semi-structured interviews, purposeful sampling would mean selecting participants upfront who meet predefined criteria (e.g., age range, current housing situation). Theoretical sampling would involve adjusting your sample based on early interview insights, seeking participants who help develop or challenge emerging themes about housing affordability.

To summarize:

• Purposeful sampling is planned before data collection to select specific participants who can provide relevant insights.

• Theoretical sampling is guided by ongoing data analysis, iteratively selecting participants to refine emerging theory.

For a focused exploratory study on housing views of Hong Kong Gen Z, purposeful sampling is a practical starting method, while theoretical sampling might be applied if you are using a grounded theory approach and plan to adapt sampling as themes emerge from data."

A collection of blog notes on using chatgpt for research purpose.