Selective attrition (the problem that some of the subjects in a study may drop out before the study is completed) is a complication in which kind(s) of study?

A) cross-sectional study
B) longitudinal study
C) both cross-sectional and longitudinal studies, but more so in a cross-sectional study
D) neither cross-sectional nor longitudinal studies

Selective Attrition

The process by which participants drop out of a study over time, not randomly, potentially biasing the results.

Cross-Sectional Study

This observational research approach evaluates information from either an entire population or a sample that reflects it, focusing on a singular time frame.

Longitudinal Study

A research design that involves repeated observations of the same variables (e.g., people) over short or long periods of time, often years or even decades.