Attrition in a study refers to which issue?

Attrition in a study refers to which issue?

• A. Loss of participants during a study
• B. Increase in sample size
• C. Improved follow-up
• D. Low data quality

Answer: (A)

Attrition means participants drop out or become lost to follow-up during a study. This lowers the number of participants contributing data over time and can bias results if those who stay differ in important ways from those who leave. It also reduces statistical power, making it harder to detect true effects. It’s not about increasing sample size, nor about improving follow-up, nor about data quality issues. Handling attrition often involves retaining participants through follow-up efforts and using analysis methods that account for missing data, like intention-to-treat or imputation, to limit bias.

Attrition means participants drop out or become lost to follow-up during a study. This lowers the number of participants contributing data over time and can bias results if those who stay differ in important ways from those who leave. It also reduces statistical power, making it harder to detect true effects. It’s not about increasing sample size, nor about improving follow-up, nor about data quality issues. Handling attrition often involves retaining participants through follow-up efforts and using analysis methods that account for missing data, like intention-to-treat or imputation, to limit bias.