Final answer:
A researcher in a qualitative research study typically stops when sufficient information is obtained to answer the research questions, or when data saturation is reached. The decision is also influenced by practical and ethical considerations, such as attrition rates and the avoidance of statistical fraud.
Step-by-step explanation:
In qualitative research, a researcher may decide to stop data collection when sufficient depth and richness of information has been achieved to understand the research questions, or when data saturation occurs, meaning no new data or themes are emerging from further observations or interviews. The decision also depends on practical considerations, such as attrition rates, where participants may drop out due to various life changes or loss of interest, which can impact the representativeness and validity of the study. Statistical fraud should be avoided, where researchers stop data collection prematurely once their initial hypothesis seems to be confirmed, without seeking potentially contradicting information that a more extensive study could reveal.
Other factors influencing when to stop include the ongoing analysis of both qualitative and quantitative research data, and the evolving nature of research questions that become more focused as patterns emerge and the researcher gains more understanding of the phenomena being studied. Throughout the research process, it is crucial to maintain ethical considerations and adjust the study as necessary to ensure the sample continues to represent the larger population adequately.