What does differential attrition refer to in research studies?

Differential attrition refers to the phenomenon where certain characteristics of participants influence their likelihood of dropping out of a research study. This can occur for various reasons, such as participants' demographic factors, their experiences during the study, or the treatment they receive. When specific groups are more likely to leave the study, it can create a bias that affects the overall results and conclusions drawn from the research.

Understanding differential attrition is crucial for researchers because it highlights the need to account for these dropout patterns when analyzing data. It ensures that the findings are valid and representative of the entire sample population rather than just those who completed the study. This concept is particularly important in longitudinal studies where maintaining participant involvement over time is essential for reliable outcomes.

The other options do not capture the essence of differential attrition. For instance, measuring participant satisfaction or increasing sample size do not directly relate to why specific characteristics lead to dropout. Similarly, assessing biases in participant selection pertains more to initial recruitment than to the retention of participants throughout the study.