What is a major threat to validity known as attrition or mortality?

Attrition, also referred to as mortality, is a significant threat to the validity of a study because it occurs when subjects withdraw or are lost from the study before its completion. This loss of participants can lead to an incomplete dataset, resulting in a potential skewing of the results if the characteristics of those who drop out differ from those who remain. When participants leave a study, the remaining sample may no longer be representative of the original population, which can compromise the findings and generalizability of the research. Therefore, recognizing and addressing attrition is crucial for maintaining the integrity and robustness of a study’s conclusions. This understanding is vital for researchers who want to ensure the validity of their results and the applicability of their findings to broader contexts.