Which method involves immersing oneself in the daily lives of study subjects?

Participant observation is the correct method that involves immersing oneself in the daily lives of study subjects. This approach allows researchers to gain a deeper understanding of the cultural practices, social interactions, and everyday experiences of the people they are studying by actively engaging with them in their natural environments. By participating in the daily activities of the subjects, researchers can gather rich, qualitative data that enhances their insights into the community's context, norms, and values.

Fieldwork is related but is a broader term that encompasses various research methods, including participant observation. While fieldwork implies being physically present in the research setting, it does not specifically highlight the active engagement with study subjects as participant observation does.

Quantitative research focuses on numerical data and statistical analysis, which does not allow for the same immersive experience that participant observation provides. Archival research involves examining existing documents and records, which lacks the personal interaction and direct observation that are essential to understanding participants' lived experiences.

Ultimately, participant observation is distinct because it combines both observation and personal involvement, enabling researchers to gather nuanced insights that might be missed through other methods.