What is a potential risk if participants drop out of a study before it is completed?

The correct answer identifies experimental mortality, which refers to the loss of participants from a study before it has been completed. This dropout can significantly impact the study's validity and reliability. When participants leave during the course of research, the remaining sample may no longer accurately represent the original population, leading to skewed results and threatening the study’s internal validity.

Experimental mortality can introduce bias if the characteristics or experiences of those who leave the study differ systematically from those who remain. For instance, if individuals with poorer outcomes are more likely to drop out, the final results could suggest that the intervention was more effective than it truly was, because only those who responded positively to the treatment are left in the analysis. Thus, managing participant retention is crucial for maintaining the integrity of research findings in social work studies.